30mm gap to fill for tiling (photo)

If the surface is going to be tiled then you don't need to get a smooth surface. Pack and screw the plasterboard on and you can tile straight awy

 

Actually it makes it both, as a standard widely accepted by building control all over the country.

 

Better than plaster direct onto blockwork do you think ? Like it used to be?

Dot n dab is just a cheap and quick system, not a better method. In my opinion anyway.

I would never put it on in my house.

 

You are right, plaster straight on the wall is a better system all round.
But that doesn't make dot & dab a bodge does it.

And in the OPs situation we are talking about an area of what?? A square foot.
So dab a piece in and tile away, instantly.

 

I will agree with that.

On the proviso nothing needs attaching to that part of the wall after.

 

I've broken out in a cold sweat, you almost fully agreed with me.