Please can someone explain to me what the difference is between
plasterboard and drywall, if any? I have walls painted with emulsion
that have a relatively smooth appearance, would this be drywall or
skimmed plasterboard - how can I tell?

Also, I would like to sand the walls before repainting them but want to
keep dust to a minimum, would it be okay to use wet 'Wet & Dry' sanding
paper, say on the end of a pole sander? If yes, what grit is
sufficient for a smooth finish, 180 or 240 - would I notice the
difference?

In article . com,
"newbietothis" writes:
Please can someone explain to me what the difference is between
plasterboard and drywall, if any?

No difference. Drywall is american for plasterboard.

I have walls painted with emulsion
that have a relatively smooth appearance, would this be drywall or
skimmed plasterboard - how can I tell?

Probably skimmed.

--
Andrew Gabriel

And is Gyproc just another name for the same?

And is Gyproc just another name for the same?

It is a brand name, commonly found on UK sourced plasterboard.

Christian.