Builder/Plumber you say?
I don't mean to be rude, I understand your predicament - honestly, we see it every week.
But why don't people choose say a Handyman/hairdresser to do the service on their car?
Or a window cleaner/dogwalker to decorate the lounge?
Builders and plumbers should stick to what they are (allegedly) qualified to do: Bricks and pipes.
Builder/plumber - well it's a small building company that claims to do complete jobs, and has lots of good feedback on mybuilder etc. Their quote was inline with the others I got.
Two different guys have been involved in doing different aspects. Problem is the guy they used for tiling obviously isn't a skilled or experienced tiler. Normally, as a keen DIYer, I'd have tackled this job by doing parts myself (labouring, carpentry and joinery), and then calling in specific trades for specific aspects (plumber for pipes, tiler, plasterer). That would have taken longer, and does come with its own difficulties, and my other half was keen to just "pay someone to get it all done",.... so I went down the "turnkey" route.
Hasn't been a *totally* negative experience, other aspects of the job have been done well, and they've not been difficult to deal with. After three attempts, the first two of which I rejected, they did eventually manage a good job tiling the three outer corners in the room.
15mm gap at bottom has now been filled by cutting 10mm strips from the wall tiles. Gap underneath of a few mm to be filled with Silicon later. As the tiles are matt white, and the grout is white - it looks ok. I'm satisfied with this mitigation.
Top of wall is still an issue. I'm going to get them to put up another layer of plasterboard on the ceiling to lower it. Will eliminate that unsightly grout filled gap.
I totally get what people say about refusing the job and having it all done again..... but right now the hassle of doing that seems overwhelming.
Will try and get pics later from my other half's phone.
Safe to say that I won't be taking this approach to the remaining aspects of the house renovation though!