Thanks for the replies.
Checked for fault codes and that is the only code showing . Checked the heater circuit on the upstream and the current was correct. Re probed it and it was showing 330mv but no switching. I thought perhaps I had probed the wrong wires at the first check but I was sure I had double, triple checked it.
Now when I probed the downstream sensor this now jumped up to 2.74v ?
Due to the no switching on the upstream I changed it but alas it was the same. Luckily my parts man said there would be no problem returning it although I don't like doing that !!!
I did advise to take it back for the VM's warranty but because he had missed his service schedule they were being awkward about it.
I have returned the vehicle to the owner till I can get more info and understand the system better.
Cheers for the adviice James and yes your quite right with what you said about probing MAF/MAP for a bit more of an accurate test. I shall do that in the future.
Once again thanks for everyone's input.
Dave