Cheers, I'm going to try another fresh install of Vista again to see if upgrading the DVD-RW firmware actually helped, so my fingers are definitely crossed with this one.
It really is quite strange though, I mean, I'd happily trial and error this problem right down to plugging in devices one by one, but because of how sporadic it seems to be, it's kinda like waiting to hitch a ride by mooning cars instead sticking your thumb out. Bad Analogy, I know