MG Car Repair: battery, 6 volt batteries, positive earth

Question
Barrie,
I have a 1969 MGB which has been off the road for six years. At that time I removed the batteries and the connections from the cables as they were corroded. I now do not know whether the car is negative or positive earthed and so don't know how to connect up my two new batteries. Can you help please?
Many thanks
Aidan

Answer
Hi Aidan.  Only the very early MGBs were positive earth.  The changeover was in 1967, so if your car is a 1969 it will be negative earth.  

Your MGB was fitted with two 6-volt batteries which are joined together to make 12 volts.  The earthed battery is on the passenger side of the car.  

Is my answer clear enough, or do you need to know how to join the batteries together?  I could attach a diagram if you need one.