Gentleman, I have embarked on fixing my B&Q wall units and would
appreciate
advice from the experts that lurk on this group. The walls I am
fixing
the
miniscule brackets on to are breeze block with plasterboard dabbed on
top.

Not that I'm saying it's the best method, but I cut out a square of
plasterboard ( with a stanley knife ) at the two attachment locations and
screwed a square block of wood into each hole ( into plugs set into holes
I
drilled in the brick ). As long as the wood is at the same level as the
plasterboard surface, you can now screw the unit into the wood blocks
(having taken care to leave a sufficient area of wood to screw into,
taking
into account the screws holding the wood blocks to the wall).

Andy.

this is how I ended up doing ours - however I just used the wooden blocks as
spacers to bring the metal plates for the brackets flush with the
plasterboard. I did try screwing the plates to the brick wall behind the
plasterboard but the plasterboard just gave way as I tightened the screws.
(plasterboard goes up quicker but I cant help thinking proper plastered
brick is so much more useful!)