Yes I'm still waiting for an answer to my question. Thanks. Steve.
As I've already stated the battery was & is sufficiently charged. (12.8v).
I shall take a reading tomorrow in the daylight & get back to you. Thanks.
It was indeed a voltage drop when under load. I'm embarrassed that I didn't think of this myself as I am an electrician!I just hope the clouds of black smoke coming out of the exhaust disappear after its been running for a while & the ECU sorts itself out.Many thanks for your help.