Nah I know its not a volume issue, everything is up full, and I've checked umpteen times.
It's still under warranty i think, as it's less than a year old. I'll pack it up and bring it back to PC world.
Might try Lenovo support first though, just in case. I'd hate to be without a laptop for a while.
Sincere thanks for the effort guys. If anybody has any aha! moments let me know, I'll keep an eye on this thread.