Good that the parents are KC registered - I still think you should check with the UK kennel club for a standard contract. If you and the breeder are both inexperienced, you might need help to put the right details into the contract. Our contract helped us get what was at that time a standard-level refund when one of our boy's testicles didn't drop, but it didn't cover the breathing issue that forced Castor to go through surgery at 18 months. Now, he's a strong healthy boy, but small (smallest of the litter, we think), and although parents are KC registered and have hade good show resultat, you never know.
On another note, although I think (standard) contracts are good, you need to consider why you want it. Will you be willing to return your pup if it turns out to have some issue? What will then happen to that pup? As such contracts are standard procedure here, we didn't think about it, but we would not have returned a pup we had welcomed into our family.
Good luck!