Cheers for the advice, I've already removed the skirting board so
it's pretty obvious where the uprights are.

As for plasterboard adhesive, I'm not sure the old plaster would take
it? I could be wrong, but I think screwing it to something solid
sounds better to me....

I've had this dilema before and tried a couple of things on different
walls:

1. Plasterboard over the original plaster. This worked fine - screwed
all the way through into the studs. These studs were not vertical
though! Be aware of that - whilst you know the location of the studs
at the bottom of the wall that doesnt guarentee them being vertical. I
used some adhesive as well, just to be on the safe side. I took off
the lathes as they were all slightly different depths and I wasnt
convinced that that plasterboard would have been truly flush on them.

2. Removing original plaster and lathes. This was very messy. And
created so much waste. However I was doing some wiring at the time so
it seemed the best option. Plasterboard is really easy to screw into
the studs. And you can see where they are too. I had to make a whole
load of additional 'studs' (both vertical and hotizontal) as the studs
were not uniformally spaced and didnt fit with the standard
plasterboard sizes. This was pretty tedious.

All in all, next time I'll plasterboard over the original plaster.

Will