The 509 is the ab-initio. The CAA approves that because it approves the methods and the syllabus for each of the schools for all relevant topics. The other CPL/IR which are not approved do not follow the preferred teaching syllabus.
Oxford and Cabair are now the only CAA approved for ab-initio in the UK. BAe at Prestwick is moving its operation to Jerez in Southern Spain - or you can elect to go to Oz. BAe no longer accept people for the 56 week course in Scotland - I imagine it will be better margins for the sunny weather; or someone is a fan of formula 1.