Got it working like a dream! And I fixed up the other shoulder button too! I got them switched in my mind when I posted this thread. The one ground down was the one working fine and the other wasn't. So I ground down the inside of the bad one like the good one and it started working better. But I also found that there is a edge that sticks out which determines how far out the button can go from the switch. This rubs up to the case and was actually forcing the button down a bit. I ground that down too and now it's absolutely perfect without any foam.
Hi
Yea, had a play with my shoulder buttons today, my left one had no foam and barely clicked at all while the right one was just very slightly
not positive but did have foam, but both did work.
I also scraped a small amount from the back of the button where the foam sticks. Then removed the right ones foam and added a small
piece of double sided tape ( the white spongy type ) on each button leaving the backing in place on the side that presses the switch, both buttons have a more positive click now
Did not think to remove some of the button that stops up against the case, but I can see that by shaving this down slightly it would give the button
better travel, that will be for next time.