On 5 Oct, 13:33, Paul wrote:
SWMBO has purchased a 4'X3' oak-framed mirror and wants it to hang on
a plaster board wall. It weighs 20Kg.
The mirror has two mounting brackets on the back which I would
describe as a rectangular steel plate screwed to the back of the
mirror with a D-shaped 'buckle' hanging off it (apologies, can't find
it on Screwfix site to get its proper name). Can I put two large
screws with spring toggles, or similar, into the wall and just suspend
the mirror off those?

thanks,
Paul.

PB fixings may be OK just in the PB, but I would try and fix into a
stud (the timber frame) behind the plasterboard. You can locate the
studs by tapping and/or pushing something through the board (in an
area definitely behind the hung mirror). If the mirror fixings do not
line up with a stud, either relocate fixings on the mirror, or screw
some plywood into the studs and fix the mirror to the plywood. You
could use a plywood "french cleat" (google for it, there was a recent
thread here).
Simon.