On Wed, 30 Jul 2008 10:31:46 +0100, The Natural Philosopher wrote:

...and if you cant plaster to save your life, use an orbital sander to
get it all nice.

But be aware of the dust it's get everywhere.

Coming in late, I'd drill out the nail hole to take a plug and refit the
box with a screw and grommits in the cable holes. Then mix up some filler
to a fairly stiff mix and fill around the box and roughly below the main
surface. Don't worry too much about getting filler into the box, wait
untill it's partialy hardened then cut/carve it out. Leave to more or less
fully set then fill to the top surface. Again don't worry about getting
filler in the box but this time use a wet float to level and polish the
surface before it sets. Wait again then trim out the filler from the box.
The main trick is a stiff mix for the filler, "soft butter" rather than a
"dropping" mix in cooking terms. That it is stays where you put it and
doesn't flow/slump under it's own weight.

--
Cheers
Dave.