We had our corner shower 'quarter circle' glass surround replaced, along with the tray, about 5 years ago. The new tray is plastic.The original tiling remained. A few months ago I moved some heavy furniture in an adjoining bedroom into which the shower area of our ensuite protrudes, to find the carpet very damp, (and ruined), the skirting board 'blown (about 80cms long), and it all smelled musty.
A bloke came and scraped out old grouting and replaced it, £150. 3 months later, it leaked again. We pulled off the blown skirting but no obvious area of leak seen, just dampness; and we took off the front curved facing in the ensuite to look underneath the shower tray, and it definitely appears it's not the actual plumbing or drainage; the line of leak seems to be below the L shaped tiled walls, and I'm aware of how well water can travel via capillary action!
Anyway, another bloke came (can't find the first and unsure we'd get anywhere with him anyway!) who re-grouted better and re-sealed the places where the frame of the glass cubicle meets the tiled wall and meets the tray.
Appeared problem solved. Except, 2 months later, the carpet in the second bedroom is now possibly wetter than before!
The bloke is coming back next week to do some other work, and is obviously anxious to sort our problem with the shower.
Bearing in mind we've already paid him £250 (so we still have a leak despite £400 being spent on it , I don't expect to pay any more for his labour this time, unless we ask him to basically 'retank' the wall altogether and put a ceramic tray in. Assuming the flex of a plastic tray may have caused the silicon sealant to break.
Please note, I'm talking about the practicalities of sorting my leak, here, not chasing anyone through small claims!