On Thu, 17 Jan 2008 23:17:27 +0000, The Medway Handyman wrote:

Now screw plasterboard bit into wood. Fill around edges.

Or if you're clever/lazy just cut a circular blank, stick in with bit of
filler or solvent-free gripfill or whatever, hold in place with 3 fat
screws in the joint locking the blank into the hole till it's stuck, then
fill rest of join & make good.

--
John Stumbles

Things don't like being anthropomorphised.