When I worked for Highland Airways, the base salary for a F406 captain was about £39,000 I think, plus a few allowances
Have a look on PPJN, not many 406's around these days but looking at all the other light turboprops, King Airs and J31/32's and bandits etc ... total package should be around the low to mid £40,000 kind of area.
Is the job with the Scottish Fisheries patrol by any chance?