With the ignition fully off, my current draw is pretty much zero, but with the ignition on (to be clear - engine not spinning, starter motor not engaged) it increases to 2.5 amps (at about 11.5v, since I've run the battery a bit flat testing this). I've turned off everything I could find that might be drawing power - now I'm wondering if the ignition coil would perhaps draw that when on? It's a 1982 Ford Capri MK3, so it hasn't exactly got a lot of electrical gizmos.
I can't seem to find any information on what I should expect as the base draw in this scenario, and obviously I'm wondering if I've got a partial short circuit somewhere.