The UK based SFO would initially have a higher salary BUT end up with a commuting command on the mainland at mainland salary...
What about the following typical EZY scenario: get based in Europe with mainland salary, then look at your roster and find out that you will be sent back to the UK for 5 days in a row in order to plug the holes in EZY´s poor (i.e. lack of) planning!
Time for ACTION!!! 