All very confusing
Thanks for the info - all makes sense BUT - maybe I am being thick here:
I had a look at the A109K2 RCFM (page 7 of App 25) says it is not certified to JAR 27 CAT A, but shows a whole whack of profiles for take-offs less than and greater than 2720 kilograms - so CAT A can be done as a back up or from a clear area with gauranteed safe reject.
A quick peek at the CAT A back up (30 m recommended) appears to be for elevated helipads (helidecks). I presume then that there is no vertical climb profile that exists for the aircraft which is typical of the rig departure profile.