Which plaster to use before tiling ?

[coylumbridge]

Our tiler will be tiling two walls in our bathroom in a couple of weeks time over a bath and shower over it.

I have removed the old tiles from the walls leaving big areas where the plaster came away leaving brick wall but other areas where it's ok. I've cleaned it up as best I can and bonded with pva/water mix.

Strap/plasterboard isn't really an option as that would bring the main wall out too far and even the 685mm wide bath wouldn't fit before the door opening (narrow bathroom).

I'm not confident about dot/dab plasterboard.

So, can you tell me which type or types and makes of plaster I should use to fill the gaps please ?

I'd then use a straight edge and paint with a bonding agent - should that be SBR, acrylic, PVA (which isn't waterproof if wet though), something else ?

I looked on various sites and also youtube and got varying ideas so just am not at all sure what's best.

Any ideas would be greatly appreciated.

Thanks