The FODCOM itself opens with:
'In the UK, the standard International Civil Aviation Organization (ICAO) phraseology “Cleared for ILS Approach“ has not been used other than for self-positioned approaches.'
and we're still not going to use the ICAO version! Nope, we Brits just have to keep that little bit of difference from 'the rest'. It'll be the ICAO words for me in the read back.