If it's not square (very common) just build it out to square with bonding or tile adhesive.
Currently, the gap between the bath and the wall is 2 cms so thats a bit too big for me to build out. The wall at the top of the bath is a stud wall so I am going to remove the aqua board and change the battons to larger sizes. What I need to know is should the bath be flush against the wall or should there be a small gap of 2 or 3mm?
Many thanks
Oh! So the bath is in a recess! That wasn't clear in your post.
It doesn't matter - 3mm play will make it easier for you to get bath in and you can give it an initial seal against the wall with silicone.
Don't change the studs on the head wall, just add furring strips to them to pack it out before retacking with the aquapanel.
Sorry, I'm never clear lol.
Just another thing, is it OK to tile the bathroom after I've fitted the bath. I'm only going to tile the bath area and have the rest of the bathroom painted.
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local