Thanks all so far ... I must say I'd be happier with 800m than 500m, so the best combination of runway length and caff recommendation so far looks like Breighton ... except that Pooley's says "refreshments and food at weekends", so I'd better give them a bell in the morning to see whether Good Friday counts as a weekend.
(I used a full 800m this afternoon, but I was proud enough of having done a decent turbulent crosswind landing off an NDB approach that I wasn't worrying about how much runway I was using up!)