Thank you both for the advice, that's helpful. Perhaps I'll try one UAP-AC-LITE or UAP-LR and then make a decision on whether it's worth moving to two. Guess I'll have to plan the placement as carefully as I can around the ethernet wall ports I have. Most of my devices are probably 5GHz capable, but I assume that the signal is less likely to penetrate as far and so I may as well stick with 2.4GHz for reliability, given none of the wireless devices are high performance things (web browsing or casual streaming). My PCs and main 4K smart TV are all wired into the gigabit network; I'm not an animal!
EDIT: Price differences weren't a lot - ordered a UAP-AC-LR and we'll see how it does.
Solid choice, what do you plan to run the controller software on?