I’ve got a cover and love it.
However I also have a tailbag that attaches under the seat.
I just put a couple of 1mm washers under the locking block.
The problem isnt the spacing between the catch pin and the lock but the seat and the frame.
Raising the block fixed the problem.
It is still a firm fit but only needs a push not a bash.
So i fitted the washers yesterday. Works like a charm now.