2. Don't bother with an edging sander, use a belt sander instead to do
the edges. Worked for us.

The edging sander is much better when you have Victorian black gunk. Whilst
a belt sander would quickly get coated in gunk, the edging sander can be
used in a flicking manoevure, which blasts off the gunk without
contaminating the sanding surface.

5. For sanding between coats of varnish, gaffa sandpaper onto an old
sponge mop-onna-stick.

Alternatively, 150+ grade grit on a standard orbital sander is excellent for
rubbing down. You can do a large room in about 3 minutes, leaving the
surface lovely and smooth for the next coat.

Christian.