Bathroom plasterboard, insulation and membrane?

[Jay9292]

Hiya I was hoping for some advice. As you can see in the picture I've knocked off the tiles which has gone to the brick. Also after stripping off the wallpaper there is an old mould patch.

Should I use damp proof membrane then batten and board?

What size battens would you use?

Do I need to take both the walls down to brick?

Many thanks

 

[FRAN1870]

Knock it back to the brick first .... You can't just cover up mould.

Secondly I used Aqua panel for wet areas before tiling ..... There are loads of ways to fix them to the wall