The newer replacement rubber rings from Axel G appear to be thicker and are causing binding on the metal locating plate.

How have others overcome this?

Do these parts actually give over time or is it a design issue?

Car is currently on jack stands so jack up the rear arm could be an issue for me.

I couldn't actually get my ones to fit!
I ended up using my original ones which were actually in really good condition.(Unlike the rest of the car)

I found that I had to give my new rubbers a fair bit of lubrication to fit correctly (copper-slip). If you can get all the pieces in the correct place/order you should be able to gently raise the rear suspension with a small trolley-jack to the point that you can do up the dampers (shock absorbers).