I only know of TG having a cadet program ab initio but I don't know who has to pay for the cost of the initial license. What I do know is that they will not look with good eyes to any Thai passport holder who is not fluent in Thai, spoken and written. It is still a government airline and contacts are still required to get in, contacts that most probably you won't have after being for so long out of Thailand (I'm assuming you have been raised in the UK). The rest of the airlines won't care as long as you have a local passport and license so they don't have to deal with work permits and validations.
If the cost is what worries you try to contact the flight schools in Hua Hin and Nakhon Pathom and ask for prices. Maybe it is something you could pay while working in Thailand as cabin crew for one of the local airlines, at the same time you could be doing the required networking to eventually land your first job, I know of several Thai pilots who started as cc.
I'm not British but the RAF path looks long and risky. Europe is always going up and down.
Last edited by iggy; 22nd Sep 2019 at 09:44.
Reason: Typo