Took the amp over to Steves on the weekend. We plugged it in and it worked fine. Good tone and crunch when dialed up. Linking channels together also good. Bit of confusion on my part in operation of the amp when Steve straightened me out on.
Took the amp home and problem back. Looking at the speaker cabinet and after a couple of emails to Steve realized I was not using the right wire to connect to the speakers. Basically using guitar cable wire. Swapped this out with proper 18 gauge speaker wire last night and BINGO there we go. Sounds great. I will do the same to my friends speaker cabinet tonight, which I also wired up for him incorrectly, and also having the same problem. He should be fine as well.
Thanks to all for responses. Someone said it is probably something simple and it was.