Interesting thread this one. I just read in our chief pilots monthly about this and we are told that our CDA rate is 69 - 74 %. But then I always thought the minimum descentrate in the TMA is 1000fpm and a snappy decent helps ATC out.
I think you 'll see our average going up quickly after this info!
And anyway, flying a smooth and stable CDA is much more satisfactory then those stepdescents.

BMI (mainline?) don't do it in six monthly checks - but do generally do at least 3 approaches into LHR every two working days (and 4-5 days a week) so get lots of practice.

CDA's are detailed in the RACAL/THALES booklets, and presumably in the Jepps as well, and my understanding is that these are extracts from the AIP. As a matter of airmanship, pilots ought to know what the requirements are for each airfield they operate to, and adjust their procedures accordingly. This specifies things like noise abatement profiles, use of APU on the ground, standard speeds in the TMA etc etc. How do people manage to operate without reference to them?! Or from another perspective, why do pilots think they are being told miles to touchdown?