Thanks for the thought. Turned out that there was an earth fault comming off of a relay. This seemes to have been draining the battery even though it had been on charge.
When turning the key to the on position the dash doesn't turn on, or lights/ petrol pump starting. . Checked the battery was charged with a multimetre which read 12.2V. All ok, and recently fixed the ignition live connector under the petrol tank. Does anyone have any pointers or a wireing diagram I can use.