Our 2 kitties just arrived here Friday morning (3 days ago). After arriving at the airport in Manchester, they then had to travel in the car for 3 1/2 hours to get to Scotland. At first, they didn't seem to be that interested in their food, and just drank some water. We didn't find any evidence in their crates that they messed themselves, which surprised me. They are just now really getting back into a routine. They didn't use the litterbox at first, but I think they are now both normal. Tbh, I was really surprised how easily they seem to have come through the whole trip. I expected them to be more scared and hiding under the bed for a week, but they are almost normal already. The only thing abnormal behavior-wise is the occasional howl they both let out (they are Siamese so usually vocal anyways).
I don't know how ours would have reacted if they went from a crate to a cattery. When we've boarded our cats before, they've just been in a kitty 'condo' (a multi-story kennel) with a view to the outside. I don't know if a cattery here is different than that. Would a cattery just be a large kennel or a larger space (akin to a room)? I know ours would not have liked a kennel, based on past experience boarding them, for a long period of time.
Food wise, we've always use Royal Canine Siamese formula, so we were pretty happy to know we could continue the same food.
Good luck in whatever you do!