AQC, AQA, Wings ATP, whatever the heck you want to call it, is open to all fATPL holders who pass the entry assessment, no matter where they trained. I know a recent OAA APP graduate who is treading water in that hold pool right now. This job opportunity is not attached to iCP, but I would put money on the eventual iCP graduates as being favoured above other FTO graduates for admission to the pool!
Damien,
You don't need 150 hours to enter ATPL theory, which must be complete before you can enter a CPL flying course. All you need to enrol on the theory course is an ICAO PPL and a Class 1 Medical. You will need passes in the ATPL theory exams plus 150 hours to enter a CPL flying course, but you can get the hours and the theory in any order you wish. OAA require that you do the theory with them in order to enrol on Waypoint for the flying portion of the training.