R
Rich
To be honest I think the water has prob done a horrible amount of damage to the substrate. Cutting out the grout and replacing it with a Silicon joint (it would be worth getting a tiler to do this) will make that joint water proof but you said that there is holes in the grout further up. Even if you have somebody in to cut out and replace all the grout, the substrat will still be ruined. As gooner has said, the entire area should have been tanked. It seems that the installation wasnt done properly from start to finish.