My last move was uk-uk and we were entitled to a hotel the night before we signed for our quarter as we had to be there first thing in the morning and our removals was due later on in the morning. However we stayed with family just down the road and were able to claim for food instead.
If you are entitled to a hotel you still need to go through the central booking agency. You admin staff we be able to point you in the right directions.
Effectively 2 nights - the night you move out of your accommodation and the night before you move into your accommodation as in many cases the removals guys take 2 days. If entitled you can also claim subsistence not only for yourself but also for your wife and depending on their ages - the kiddies. The guy above is right about having to book via CHBS.