walls not as true as they look!

[solddowntheriver]

Hi all, I have cleared out my bathroom and removed all the tiles from the already plastered walls, but alas some of the main wall is not level, (about 10 mm out of true, like a bow) the plaster appears sound and solid to knock. Do I re skim the existing and make true or take down all the plaster and then dot and dab/ mechanical fit board on this wall or use a deep bead of tile cement and work the bow out that way?
Tiles are 250 x 450 ceramic 8mm. I wonder whether just to take all the plaster off the whole room and board out before tanking the shower area, or am I just making work for myself?

 

[AdamCH]

If it was me, I'd take the plaster off and re-board it. Don't try to tile walls with a 10mm tile bed. Remember a 10mm notched trowel will produce a 5/6mm bed. A 10m bed it way too much.

 

[solddowntheriver]

Tbh I agree with you Adam I think my common sense gene says just take it back to brick, board it, tank it tile it then forget it.