The reliable way to hire a tradesperson

Had a loft wetroom fitted. Before getting to use the shower I noticed the grout had come out and tiles were moving. The room was impey tanked but I think the floor boards were only nailed down. As the rest of the loft I had to go around and screw all the boards down before the carpets went down. Is there anyway I can take the tiles up and the impey membrane and reinforce the subase? Without having to remove the wall tiles? It's cost me a small fortune so far but it's just a waste of space at the minute.

I have a builder fitting a shower bath and tiling the walls and floors. Before he arrived I fitted the new basin and toilet myself. It's all been going okay until he asked me to take out the toilet pan so he can put the new tiles on the floor. After back and forth it seem he's unwilling to cut one of the tiles to fit around the toilet because he thinks it will look bad. I am genuinely unable to move the toilet pan for several reasons. Should I try to cut one of the tiles to shape myself for him to fit or should I tell him to not put the floor tiles down and I'll find someone else?

Hi all I am currently re-doing my spare bedroom. It is a typical victorian 2 up 2 down. The bedroom has a fireplace on one wall with two alcoves set back on either side - extremely typical for this sort of house, if you google "victorian fireplace alcove" you will find hundreds of pictures of what I am talking about. The wall with the fireplace has (from one side to the other) two internal joints, then an external joint, then the fireplace, then another external joint, then two internal joints. I am going to scribe the skirting to fit the internal corners and mitre to fit the external corners. My question is for the joints I am scribing, how do I know which side to lay flush against the wall, and which side to scribe to the profile of the side that has been laid flush against the wall? Does it matter, or is there a trick to know which will look 'better' when all is said and done? Is it a no-no to scribe both ends of one piece of skirting board (for example the boards that will be up against the back of the alcoves either side of the fireplace), or are you supposed to try to ensure that where you have a number of internal joints in a row, each board has one side flush and one side scribed? Many thanks in advance & I hope this makes sense.