Fitting plasterboard & lime plaster issue

[SparrowHawk99]

Two question,

I've got a stone wall with a timber stud adjacent to it. I'm boarding the timber stud with 12.5mm plasterboard and I've reached the section where the stud meets the wall. The wall is stone so not even remotely flat. It had a layer of old 20mm lime that I have removed because the whole surface of the wall is to be reskimmed. How do I scribe the board to the wall? Furthermore, when the walls come to be plastered, will the lime have a negative effect on the plasterboard?

 

[notfilc]

Disclaimer: I'm not a pro so I'm sure you will get some better answers but this is the way I'd probably go:

Use joint filler to fill the gap between the board and the wall.

Scrim over the joint filler and around the corner to the lime wall.

Use something like easifill on the other wall to feather the scrim in to the existing plaster, or if you are going to reskim that wall then just skim over it.

But as above, there is probably a better way to do it.