the company I'm contracting in at the moment is not UK based and have some "special" ideas...
Taken from
http://www.caa.co.uk/docs/33/CAP549.PDF
NOTE: Configuration Deviation Lists (CDL) or their equivalent, are not a part of the
MMEL and are not dealt with in this CAP. CDLs are used to identify any
external components of an aircraft type which may be missing for dispatch,
where necessary, they will provide any associated information on
performance corrections for such cases (e.g. missing landing gear doors, flap
actuator fairings, etc.). Where dispatch with such items missing is approved,
the CDL may be published as part of the CAA/JAA approved Flight Manual.
Hope that helps a bit