Thanks for the info Louis II - Link did'nt work for me but your mention of tube of glue on the parts list is proof enough.
I've now removed B + C + D pillar cover panels - They just pull off. Popped out the 3 interior lights and the 2 aircon vents. Removed the tailgate area roof trim. Doing all this reveals a number of small metal fixing bolts on the actual trim piece i needed to remove. Although this loosened the trim, it still would'nt budge along the top edge of the panel. With no other visible fixings and nothing else obvious to remove it's got to be glued - which begs the question of how you are ever supposed to remove it!
Luckily with the fixings and other panels removed there was enough movement for me to hook the cable i needed to access, so for now job done. Still annoying I could'nt remove the panel completely though!