Wheeey...looks like I could be getting somewhere now.
Checked the reg red to bat pos and got very low (ie 1ohm) reading.
Striped all of the wires back checked all connections. One was dodge so replaced. Cleaned up the earth contact for the connector on the reg. Cleaned the contacts on the bat terminals. Replaced buller connectors on the yellow wires.
Started her up and he presto...13.5V across the bat

Thanks for all of the advice guys...mucho appreciated.
Bring on the sun
