OK, rear end packer and this took a lot of thought. I ended up spending ages making a nice thin wedge and then microing it to the back of the cover as I did at the front. Of course this then needed a ply of BID as you see in pic 2 and then the edges sorted out with a smear of micro.
Pic 3 shows that I'm preparing some stoppers or spacers that will sit on that stainless steel foot on the gear leg. I want it all sitting flush in the end and happily secured. That foot was what caused the need for some thinking.