Cheers hux, the prob isnt getting the panel in, it fits around everything fine, its fitting it in between the two bits of trim where it wedges into the sides just above the rear compartment lights
Potentially I could make it one piece and put it in first before the boxes but my god it was a pain in the arse to get the right shape initially without having to pull boxes in and out to fit it in, thinking about it though it may be the only option....
Other options running through my head are to mount an extinguisher on top on one side and a med kit on the other? Would cover the join partially while adding some extra safety to the car?