I had a shower tray fitted (badly) and it is about 10mm out from the wall all round. I have fixed the gap with silicone and tile slithers to bridge the gap and tiled down onto it. BUT.... I now find that the shower screen will not meet the wall even with the adjustments allowed. Would it be possible to attach a plastic strip behind the wall bracket, with screws and silicone, to compensate for the gap, or do you have any other ideas?