I would have jumped at leather if it was an option for me, do you have kids.
Before we had children I thought no way to leather, cant get it dirty with mud, sand, water etc etc, but now we have it in both cars & the lounge room LOVE it.
They are so easy to clean, sand & crumbs - brush it off, mud - damp cloth wipe it off, sticky drink - warm cloth wipe it off, all with no trace or stain.
Sure the seats in the car get hot when they are in direct sunlight, but it's only a short term discomfort & warm up quick in the winter, I wouldn't think the seats in the caravan would get all that hot compared to a car.