Thank you for your reply - and yes very frustrating - we were told that the wall end for shower controls was too thin - having already scoped and agreed they could go there?!? Also it was scoped that the radiator could be hung high up on wall - this was scoped for and then we were told that there were too many wires behind that wall?!? Does not give tradesman a good name.
The wall may very well be too thin, and although you was told the shower could go there, your plumber may not have checked before agreeing this with you, this would be an error on their part. What are your walls constructed of?
I can't comment on the wires, There shouldn't be any there but there's always the option of moving them but again, that comes down to communication and price.
As
@YorkshireDave has said, I shouldn't be bashing another plumbers work without knowing the full story.
So I will say that from my own experience with bathroom installations (and I install around 40-50 a year). I can say that very rarely does an installation go to plan, I am constantly torn between what a customer in their eyes has been sold and what our bathroom designer has sold them.
However I can also tell you that 99% of the time there is a way round problems. Whether it be, in your case for example, boxing the wall off to allow the installation of the shower valve where you specified it and installing a smaller shower tray and screen, or changing the shower for a more practical one like a digital Mira or aqualisa. Again this comes down to communication.
I would in my opinion lay the blame more with the installer in this case as common sense would clearly show that the shower is impractical in that position. But did your husband not raise any concerns after the valve was fitted but before tiles went on the wall?