The CAP where it's recommended is CAP 667 (9.2 (c)) to be precise, although there it's only a safety recommendation / suggestion for airfields.
AOPA have a list of those who have (and those who have refused) to sign upto the scheme. The following is as of Jan 1st 05
http://www.aopa.co.uk/newsfromaopa/aopa189.pdf
If that's not enough, AOPA will at least be able to point you further in the right direction.