I refer to my earlier post about the eventual scope of the programme. This is the start and it is a measure of the trust that Turkey normally guards closely, that it is prepared to partner with BAES and HMG.
Moreover, Geography doesn't change. I agree that the trajectory of Turkey doesn't look to good a the moment, but it is the extended Front Line of the UK in terms of defeating Daesh, counter-terrorism, reducing irregular migrant numbers, interdicting organised crime (narcotics, people smuggling etc) and is NATO's southern Flank against Russian expansionism. For these reasons the UK has to have good relations with whoever is in charge...added to the fact that c 2 million UK nationsla visit Turkey every year as tourists.
In October 2015 Turkey asked for assistance from NATO to provide assurance against increasing Russian aggression. The UK responded very rapidly and within a few days there was a survey team from High Wycombe and PJHQ, surveying Incirlik Air Base, with an view of deploying Typhoons as a deterrence measure. The MOD made that offer through NATO...but we were the only country who was prepared to pony up assets, with other countries viewing this as a Turkish problem. If the call had come from Poland, for example, I am sure there would have been a more robust response from the Alliance members.