This is what I recalled:-
“It is not sufficient for a runway to be considered, for performance purposes, as dry when it is wet solely on the basis that it is constructed with, for example, grooves or porous friction course pavement. Dry runway performance must only be used when the CAA has accepted in writing that the aeroplane can actually achieve the “effectively dry” braking action referred to in the EU-OPS definition.
However,
there is currently no provision in the UK for notifying operators of runways having such surfaces, and the CAA is not aware of runways elsewhere that fully meet the “effectively dry” criterion.” (my bold)
Ref
http://www.caa.co.uk/docs/33/FOD200903.pdf
Also see
http://pilotlab.net/aircraft-manufac...oved-runwa.pdf
N.B. this is dated 2006, so LCY probably not considered at that time; also that take-off was cleared but landing was not.
The acceptable test methods are on page 5.
IMHO, the requirement for a ‘specially prepared surface’ implies the need for regular maintenance and reporting; hence back to the CAA FODCOM.
Repeating the point, LCY is not the place to push the limits.