Enclosed garden. But please put the bins, and any compost bin, in a secure area so that when children are playing in the garden you don't have to worry about their curiosity for the compost heap ...
Television capable of USB (so we can bring Chromecast). Please fix it to the wall or to a cabinet, children shouldn't be able to push it off the table. Oh, and please can you regularly re-tune it, preferably after Freeview move their channels around? Or if you're not going to do that, don't change the password and prevent guests from re-tuning it for you.
No ornaments, no pot-pourri, no dried flowers - nothing within child arm reach. I don't mind ornaments on a high mantlepiece, but I'd rather not have to 'child-proof' the room.
Large mugs. (We tend to bring our own.) How about a range of mug sizes to please everyone?
Tell me if there's a dishwasher, and we'll bring enough tablets for the week.
A casserole dish! I like to make oven curries, or at least slow-heat two or three portions of shop-bought curry.
Don't give us a set arrival time, be flexible (key caddy) or live next door. Driving is stressful, worrying if we will be early and need to kill time or be late due to traffic just makes us frazzled. We are not responsible for the traffic on the A30.
DH would say "a deep bath".
Wifi of the fastest that you can get (we accept that sometimes it is rural and therefore pretty slow).
If there's an obvious children's bedroom, don't have pictures on the wall / wall cabinets (I'm looking at you, Haven) / wall lights / television in grab reach. And put simple cabinet locks on the wardrobe (after you've fixed the wardrobe to the wall).