Going dark. Dark blue on the walls. Would probably get a grey on the woodwork but might leave that.
Ask for two quotes, with wood and without. If they're not confident of doing the walls and ceiling in a day, then the difference might not be drastic. Make sure to tell them it's grey for the wood, as that will need grey undercoat and ideally two top coats. I did a banister in grey eggshell recently and it looked mint.
Prices vary of course, and it will depend how local they are if they are having to come a few times, but I'd say expect £250-300 for the whole lot.
I reckon you should go red and white
'STFC, on yer walls!'