I have also just done this and there is no easy way, although ther is a cheaper way, Simcom offers the full 800A type with 700 differences for $15300, if you do it without the 700 diffs or you do it with XP diffs it is $18K
So get the PPL validated at a FSDO, Get your TSA stuff sorted after you have booked the full type at Simcom (cant be done other way around),if you meet the requirements for FAA ATP/ comm then sit the test in Blighty before you leave. HS 125 Course is 16 days at the facitliy in Orlando, and the type rating checkride includes the ATP check. I was in and out in 20 days including the fingerprints which I did at Pan Am in Miami as I was leaving from Africa.
Good luck, its a great course and great machine