I'm in a three-piece based in Scotland. We play mostly hotels and pubs. Fee varies between £150 - £300 (top end for Hogmanay,St Andrews Nights). Sometimes we have free accomodation and food provided.For this we usually do three sets of 50 minutes each.
If we are booked for one hour, two hours or three the fee is not affected as your day/evening is spent preparing and packing PA, and travelling.