Sorry, I thought Si's suggestion was that the latch was faulty, mine was neither loose, nor faulty, it was just adjusted poorly. I should pay more attention, and do very much appreciate the suggestion though!
Exactly as Jase said, the catch is held in place by two torx bolts, strangely mine was at a slight angle. I just straightened it up and moved it back a touch, and job done.
To remove the trim, there are two push clips in the top of the trim, these just pull out, then two 13mm bolts holding the load tie down eyes in place, finally just tug the trim vertically upwards, starting from one end.