Hard to say. I would have to divide it up into different categories. Of those I'm prepared to make public, the weekend in which Temple Sutton School won their first ever National Title (1992) was very special. We won the under 11s, another Essex school (St. Teresa's, Colchester) won the under-9s. Because of the cost, the only adults to travel with our team were the head, the parents of one of the girls in the team (our team was most unusual in that it was 50% girls - most are 0% girls) and me (my daughter was on Board 2). I was on good terms with the St. Teresa's parents as well, which made it one great party (the venue was Pontins, Brean Sands) and all the private schools really had their noses put out of joint when two
state schools with scruffy children (ours didn't wear uniform, have specially made sweatshirts or anything like that) took the prizes. Normally the posh kids get to clean up.
Possibly the best match was beating Ipswich Prep 4 - 1. They were coached by a certain Kevin O'Connell, who was Something Big in the World Chess Federation, and had England u11 players on boards 1 & 2, and possibly 3 as well. Indeed, one of these,
Nicholas Pert, went on to win the World u18 Championship six years later.