I think I may have worked out what the problem is.
I dont think the dongle I have is Vista compatible, because neither the Windows Bluetooth Wizard nor Nokia PC Suite will connect to it. The only way I can connect to anything is through the Blue Soliel Desktop that came with it. Although I was told it was when I bought it, having read the packaging it makes no mention of it.
I am therefore going to get one that is Vista compatible and try it again.
I will keep you informed.