Slightly different but my MGB has the battery under the seat. Before my recent rewire I would flatten the battery at least once a month over winter by leaving something on.
Fitted some heavy duty leads with an anderson connector that went into the boot/spare wheel well. Then had a set of 3 metre leads made up with an Anderson one end, and crocodile clips the other so I could easily jump of the other car, or a loose battery.
Like the one in this link -
Ebay - Anderson