Renovating first house, need advice.

[itidiot]

Build the wall straight is defo the answer. It will be quicker in the end and make the finish far better... seriously i've just done my first bathroom and dips in walls are nightmares (look on here for lipped tiles to see what will happen). I would be like you if faced with this problem not wanting to sort the wall out especially if its just been done but it will be worth it. get some concrete board/tile backer and screw to walls.

If you really dont want to sort out the walls take a look at this video... cut the high point out where top of bath roll meets wall (he draws a line on the wall). I wouldn't make the wedge though
toms top tips.fitting a bath - YouTube

 

[kendo1]

What you need is one of these:[video=youtube;WVdzP53X9vw]http://www.youtube.com/watch?v=WVdzP53X9vw&feature=related[/video]

 

[doug boardley]

what tiles are going on the walls anyway? unless they're ceramic (as opposed to porcelain, natural stone etc) the skimmed plaster won't bear the load.