DH grew up with parents who have the thermostat set to 23 degrees day and night - to me this is swelteringly hot, and I sleep without covers on (or the window open if I can get away with it!). My parents, on the other hand, set theirs to 18 or 19 degrees during the day, and 16 degrees at night.
DH prefers a warmer house, I prefer a cooler one, so we have frequent heating wars!
What do you consider a 'normal' temperature for a UK home?