Well this really sucks. Took the car back to the dealer, was told that Nissan Technical recommended replacing the alarm control module (agian?) but this was on a 18 day back order ...
The part arrived, was fitted the guys at the dealer drove it around for a couple of days. Returned it as OK, and before I could pick the keys up from the reception at work the alarm was going off ...
Had enough now looking to get my money back!
Thanks for the help though