Actually the CAA have been very public in highlighting the differences that they have adopted in the UK. NATS recently made a DVD for aircrew to hammer home what the UK differences are and why the CAA have decided to use these different items of phraseology!
I have not seen (in the UK at least) any mention in any AIP as to what the differences from ICAO are, so I suspect it is not a requirement for such details to be published in a AIP!