Finally I got down to the plaster! It seems to have some sort of buff coloured paint on it. The house dates back to the 1700's and I think this might be the first layer of paint ever put on this wall so it is pretty old paint! I am going to have a look at heritage paint colours to see if I can identify it, not that I will be painting the walls back to this colour as it is a bit drab - maybe that's what the paint is called - drab. Anyway, they certainly did like their decor gloomy all those years ago!
On this wall the plaster and the paper came away but it has revealed the lath and plaster and some nice oak beams which we have decided to leave exposed and just plaster in between. It would be a shame to cover them up.