Hi Clemens, it sounds like you have already fixed the issue. If the Plus Four is the same as the Plus Six then in the standard setup the 4 screws that hold the aluminium handbrake trim in place ( and the rear of the centre wood section ) are two different lengths.
The screws that are toward the front and to the rear are longer as they go through the aluminium trim then the wood and then screw in place into the lower chassis alloy, this holds the centre wood section firmly at the rear.. The screws on the passenger and driver sides are slightly shorter, as they just hold the aluminium trim to the wood. I noticed this when I changed the gear lever, I think I may have mentioned this in the write up. Not sure if MorganPark used the standard screws and maybe mixed up the lengths/positions, or they fitted their own to hold the new holdall. Anyway, just a thought....
Dave