The car will sometimes crank no start.
Battery would also run flat when he gets up for work.

He's had several mechanics and electricians look at it but still has an issue with it ever since his van was in flood water, but after further discussion, it wasn't high enough to reach the ECU but still a concern. In the last year he's had 3 batteries fitted and a new alternator.

New battery tested was on the low end at 300cca. Initial scan logged b2799 immobiliser communication only in the ECU. Both keys disable the security light on the dash when inserted.