"In light of Shelvey v Evans," begins Rod Roberts, "has there ever been an instance of two players being sent off for the same tackle?"

After a lot of fruitless searching, we finally stumbled across a report from the Northern Echo that tells us that this actually happened right at the start of last season, in a match between Hartlepool United and Walsall. Just before half-time, Walsall's Andy Butler and Hartlepool's Nathan Luscombe (who'd only come on after 20 minutes because of an injury to Nobby Solano) were both sent off for a hard, low tackle that left both men smarting but little more.

"I find it hard to see even a yellow card for each player," said the Hartlepool coach, Mick Wadsworth. "No one goes in two feet, Nath is on the ground, one foot on the side, their guy tumbles over him and falls on top of him." Both he and the Walsall manager Dean Smith made the kind of argument made by the Sky pundit Gary Neville following Jonjo Shelvey's dismissal against Manchester United. Said Wadsworth: "If you thought it was a nasty foul, even then, common sense surely: two guys tackling, two yellow cards."

"Butler goes in one leg, wins the ball, their lad comes in for the ball," said Smith. "Both cautions, if that, and both players were very unlucky."

Another story, dug out from the dusty archives of the Sports Argus, concerns a friendly between Nuneaton Borough and Bognor Regis in 2004: 35 minutes in, Brian McGorry and Guy Rutherford were both sent off over a coming together that the Borough boss Roger Ashby described as "both players [going] for the same ball and [ending] up holding each other down". We've only got his word for it, mind, so if you know what happened that day, why not email in?

Most other double sendings-off (those hours trawling thousands of match reports won't be wasted, after all!) involve some kind of brawling/elbow swinging/kicking in the ribs/forehead pushing, our favourite being the clash between Joe Baker and Ron Yeats in a 1964 cup match between Arsenal and Liverpool. Yeats ploughed through the back of Baker, causing them both to land on their backsides, and Baker – half Yeats's size – promptly got up and landed one square on the Liverpool defender's noggin before sauntering off down the tunnel without even waiting for the referee to raise his card. Yeats was sent off for the original foul.

GROUNDS THAT ARE ALMOST SYMMETRICAL (2)

In last week's Knowledge we looked at grounds that were as near to symmetrical as dammit, and you have nominated some more …

"Regarding the three football grounds in Blackpool described by Michael Haughey," begins John Vint. "The centre spots of the three are virtually in a straight line, from AFC Blackpool, 286.61 metres to Squires Gate FC and  366m to the centre spot of the Wren Rovers spot. In addition to these, however, behind one goal of AFC Blackpool's pitch  there is Collins Park, 'The home of Sunday football'. With 266 metres between the centre spot of AFC Blackpool and the main pitch at Collins Park  and 374 metres from Collins Park to the Wren Rovers centre spot, this makes it a perfect football triangle (give or take a few metres)."

Iain Thomson, meanwhile, has suggested the Vasil Levski National Stadium and the Bulgarian Army Stadium in Sofia. "While not quite right next to one another, they are both aligned along exactly the same axis," says Iain, "and the Bulgarian Army Stadium has a speedway track right next to it to boot."

"In the Netherlands, two of the foremost amateur clubs, Ijsselmeervogels and Spakenburg, hail from the same village of Spakenburg," emails Justin Hughes. "Their derby is one of the most famous football fixtures in the Netherlands, more famous than all except Feyenoord-Ajax. As you can see from this Google map, their grounds are back to back. There's more on this wonderful derby (known as the spellcheck derby!) here."

There's more. "The old and new stadiums in Malmo, Sweden, are right next to each other," writes Henrik Persson. "Both Malmo FF and IFK Malmo used to play at Malmo Stadion. Malmo FF built the new Swedbank Stadion just to the south and IFK Malmo still play at the old one."

And Mark van Dijk adds: "I thought I'd add in another pair: in Durban, South Africa, the Moses Mabhida Stadium (which hosted the 2010 Spain-Germany World Cup semi-final) is right across the road from Absa Stadium. Now while Absa Stadium is technically a rugby union ground (it's home to Super Rugby's Sharks), it has hosted football matches in the past … including a 2003 friendly between South Africa and England, in which Gareth Southgate scored after about 30 seconds."

THE WORLD'S GREATEST LOWER-LEAGUE MANAGER

"Which manager is the greatest lower-league manager in the world?" wonders Claudio Alegria. "Meaning, who has got the more promotions and/or more clubs promoted?"

"Don't know if it's a record, but Dutch coach Frans Körver managed to take six Eerste Divisie (First Division) teams up to the Eredivisie in the Netherlands during his career in the '80s and '90s," says Johan van Slooten. "FC Wageningen (1980), Fortuna Sittard (1982), MVV (1988 and 1997), VVV (1993) and De Graafschap (1995)."

Körver is beaten by a couple of obvious names from England: Neil Warnock and Dave Bassett, who have each presided over seven promotions. Warnock's were with Scarborough (1987), Notts County (1990 and 1991), Huddersfield (1995), Plymouth (1996), Sheffield United (2006) and QPR (2011); Bassett's came with Wimbledon (1981, 1983, 1984 and 1986), Sheffield United (1989 and 1990) and Nottingham Forest (1998).

Can you go higher than a seven? If so, email the usual address.

KNOWLEDGE ARCHIVE

"I am interested in learning the origins of the expression that a defence was at 'sixes and sevens' in dealing with an attack," said Eric Willis back in more innocent times. "Can you help?"

With Susie Dent declining to return our class, we go off to www.wordorigins.org to answer this one, Eric. It states: "'At sixes and sevens' is a very old catchphrase and relates to gambling. It first appears c.1374 in Chaucer's Troylus. The original phrasing was 'set upon six and seven'. It referred to betting one's entire fortune on one throw of the dice [this, it transpires, being a game called 'hazard', more commonly known as craps]. It connoted carelessness, and over time the phrase came to mean confusion, disorder, and disagreement." Apparently a plural form, 'to leave at sixes and sevens', was developed in the 1800s; it was still based on the same gambling metaphor, but the idiom was now used to signify a kind of confusion or neglect, rather that pure risktaking.

For thousands more questions and answers take a trip through the Knowledge archive

CAN YOU HELP?

"The last time the Welsh national team drew a match was November 2007 (0-0 away to Germany), 41 games ago," notes Leon Barton. "Has any other team (international or club) gone this length of time without drawing a game?"

"Port Vale's Ashley Vincent recently scored in three consecutive games," begins Nigel Stubbs. "Nothing unusual about that but in each match he was wearing a different coloured shirt (white vs Rotherham, pink vs Plymouth and yellow vs Fleetwood). Has this ever been done before?"

"Who has been caretaker manager most amount of times or for longest without getting the job full time?" tweets Greg Fidgeon.

"Between 1935 and 1945, Burnley were managed by a selection committee," says Justin Hughes. "Is there any other case of a noted club having had selection committee management for such a long time?"

"In 2009 Carlo Cudicini broke a rule in his contract about riding a motorcycle when he suffered a nasty crash a few years ago," says Duncan Palmer. "Is it common to have such bans regarding bicycles? Are there any players past or present who are cyclists? I can't imagine that many arrive at training on a Pinarello or Bianchi …"

Send your questions and answers to knowledge@guardian.co.uk.