I take it no one else has had the same problem... Anyway, my last canvas varnished without problems, in case anyone else runs into problems here's what I did...
I bought a cheap 5x5m poly dust cover and taped it to the wall behind my varnishing table about 1 metre above the level of the table and created a tent-like structure and varnished inside this, sorted out the dust problem. As for the hair (I've got a dog) so the only solution was to varnish in just my pants as hair on my clothes is pretty unavoidable. The odd globs I was getting were bits of old dried on varnish on the foam roller, I hadn't noticed this before so I replaced this and it's better now. I think that this particular canvas is just a little less forgiving than the cheaper canvas I used before without problems but at least it's forced me to be a bit less slap dash about finishing.

sQ