Daz I would never have a collie, they require more care than I could ever hope to give them. I was not referring to a collie rescue centre, rather a local rescue centre. The rescue centre is very picky about where dogs go, in fact probably too picky.
I know of dogs that are routinely left at home all day, I also know of dogs that go to someone elses house for the full day. At the moment mine is left between 8 and 12 and the 1 and four, he seems fine with that. When my mum and dad are back from holiday he'll be with someone for the afternoon at the very least. When he's on his own he enjoys the peace and quiet, when we go on holiday he's knackered by the end of the week and looking forward to us going back to work so he can get some peace! When I'm off sick he just stays on his bed all the time.
Apologies if this seems overly agressive but I'm left feeling a bit defensive from what you wrote.
I do think it depends on your dog, I have a particularly lazy labrador, who only retrieves in water, likes to sleep, and spends most of his time a hundred yards behind me because he's found another interesting smell. At least he's stopped peeing on every gate post we go past now!