Tile board sealing and leaks

[Eric125]

My plumber fitted a shower, 2 of the walls are glass panels and one is a tile board (wedi board). He joint the wedi board pieces (3 pieces) close to each other but didn't use any joint sealant. When I asked him whether this will be an issue for future leaks he dismissed it. How worried should I be? The wall made of the tile board will have the water tap and shower head on it so water will be moving away from it however it will still get wet from splashback and steam running down the walls. I understand that his installation is not as per manufacturer's instructions but the wall has now been tiled with 500£ worth of tiles so I am trying to establish how much of an issue his short cut will be.
To make things worse he grouted the tiles on the same day that he installed them.

 

[fowlerboi]

I wouldn't worry. The fact he's used a decent water proof board is 10x better than the majority of installations. The openings where taps and stuff are will all be sealed and steam won't get behind unless you treat it like a sauna.

If he's used a decent tile adhesive then grouting the same day is fine also