Easy peasy. Went in from the outside from the windscreen area, as Joe said, you can just lean back the plastic gutter and push the lock mechanism back with a thin screwdriver, damn sight easier than its been for years using the handle and cable!
The cable was fine and free moving but its so long and convoluted, I think that's most of the problem is, that it must be over 1.5 metres long to just pull a 1cm movement, only needs a small amount of stretch and it wont open.
Plan to set up a shorter version of the cable and handle and not use an aero catch.
Thanks all, as useful and helpful as ever.