Hi team,
in way of thanks I have uploaded some photos (to my gallery) of the tools and method I used.
There should be:
A side image of the clips showing the backside that digs into the frame (looking down along the line of the trim)
A closer version of same
The tool I used (buying that expensive tramp a while ago finally paid off - the hook is the spring puller)
Showing the door frame (at the lock), you should be able to make out the clip hole in the top right of the "lock" hole. The Hook is running from top left to bottom right and the point of the hook is in the "lock" well (at about the point needed to push the back of the clip up)
Same "lock" hole without the hook in image
Same "lock" hole showing roughly the angle I has to use the hook at.
Finally: the clip point closest to the door hinge, showing the hook "up and under" the frame pressing up on the back of the clip.

I found that a little upwards pressure with the hook was enough to pop the top of the clip out enough to grab with a pair of long nose pliers.
Put into trim in the right place, re-seat.

Job done!

Thanks to Andrew for pointing us in the right direction.

Dave