Hi Paul - welcome !
Much the same as you - run an Avon adventure from Xch for years ( and still often do!) .
My kids are bigger now so I've been looking for something to suit for same sort of usage (but without the need to get kids in it anymore)
How old are the kids ? They get bigger very fast - so if its a case of jockey or bench seats etc .
Most builders make something that will do it - however my choice has come down to Ribcraft 5.35 or 5.85 ( with 2 or 4 jockeys) or Ribeye 5m ( again side by side jockeys) . The longer the boat the more seat choices you have.
There are however so many other options out there .....I'm sure they will get suggested soon.