Er, no. The Navman bod was very confused. though I have to say, hats of for volunteering to com down on a Sunday.
He is of the opinion that it is a software issue,as the installation is ok as both sets of senders work independantly, but not together. When both joined the control unit constantly re-sets itself. He is going to call me tomorrow to see what the latest software is - mine is version 1.8. They are also going to replace the T-Peice