squaring up the walls for tiling

[MikeMaMan]

Hi guys. I am on my first bathroom project. My walls are thermalite blocks and one wall is a brick wall. Tiles will be 600*300 10mm thick porcelain. Brick wall not exactly flat (deeps up to 10mm here and there), but overall level is not too bad. So i have two questions.
1. Should I render it with sand and cement or just use more adhesive?
2. I use dab n dot where i can, but i got to this corner where the walls are out of square by 45mm. Brick wall is parallel to the other wall, so i need to fix block wall. What would you guys recommend? I think of having plaster board on it before tiling. But can i dab n dot 45mm?

What do you guys suggest?

Regards. Mike.

 

[foxhole]

I used insulated plasterboard on all external walls, [never hurts to improve insulation], internal walls can be coverd with plasterboard or aqua panel, or similar, around wet areas.Fixing with foam adhesive copes with just about any size holes.

 

[MikeMaMan]

I have an idea how to do it. Where i got the biggest gap (where i will have bath installed), i will make a wooden frame and screw on hardie board. The rest of the wall will be dab and dot plasterboard. Should work right? I will Waterproof it some tanking paint later, before i start tiling.