At last....... It turned out to be the tail wires that go to the battery.

I guess they'd just had their day and called it a day.

I replaced them as suggested with new and larger wire (35amp) got some decent connections and wired them in along with a 30amp fuse on the tail wire that had obviously been getting hot. (The fuse was just a safety measure incase there was a problem further down the loom. But it appears not.

Now I'm getting 13.5 volts to the ecu at idle with no ancillary electrics on.

And with lights on full beam, and wipers on full chatt, I'm still getting 12.5 volts at the ecu.......And the fuse hasn't blown.

At last.

Assuming this was the problem and I've solved it, I just wanted to say a big thanks to everyone who gave me suggestions as to what the problem might have been.

At least now I know that every earth lead has been checked, cleaned and is working properly, and I've gone through the fuse box connections, relay connections and about every bloody electrical connection on the car. So electrically, it's as good as it'll ever be.

Big thanks to everyone, and I'll keep my fingers crossed that the problems solved.

Basically, I have good power going to the ecu, even with ancillaries on. So no Karl can get off his butt and finish of the mapping.

Best Regards and thanks for your patience with me.

Jim (Know more about car electrics now than I've ever done....Which still isn't much).