I'll keep the thread updated.
I'll have a go with PB suggestions tonight for the backlight on the screen.
I'm trying to make it as easy to use as possible, so the rest of the family only have to press a power button and then they've got control over the whole thing. To that end, I'll need a volume control as well, so I've been reading
this about putting a potentiometer in as a volume knob. It's written for Volumio, but providing I can get the stuff they suggest into Libreelec it should be ok.
In my mind the screen'll be mounted flush (or as flush as can be) in the wall, all wiring hidden away but the power taken to a switched mains socket in a cupboard underneath the worktop. I'll have to find a way to make it easily removable, for upgrades and what not.