The issue is now fixed, apparently there was a break in the transmission positive supply wire (red) to the TCU through the large round multiplug wire between the boot fuse box and the transmission multiplug. He cut the offending wire out and fitted a new one. Took him about 3 hours in all. Very happy now.

 

Issue with DB9 wont start now fixed turned out to be the positive (red) wire from the boot fuse box to the transmission multiplug had a break in it and was not giving power to the transmission control module (TCM). Took the auto electrician 10 minutes to find it and about 3 hours to remove the offending wire and replace it. Very happy now.