Average re-skimming cost

[Raks]

After removing old wall papers and all ceiling coverings, now the house need re-skimming.over the original hard smooth render.

All layers cleared fairly but may need sand papering in small areas.  Surfaces are not damaged, they are smooth & hard but ceiling have cracks so better to put a layer of mash rather than taping.

Net wall area is about 290 sqm and ceiling about 95 sqm.

What is the average  cost of re-skimming in SE London area and as a separate estimate for painting?

 

Should I expect a price per sqm Labour + materials or all inclusive?