checking battery leakage current

The message from "shazzbat" contains these words:

Or less from this bunch

It would give wildly inaccurate results when measuring ECU sensor voltages though, due to the low impedance - and some say may cause damage. But probably better for circuit checks on lights etc due to the same reason.

Quite a few of these old batteries are still available. Think Rapid have them - certainly for the Model 8.

Or you can buy the adapter from

ISTR that it had a very sensitive meter and hence there would be a large multiplier resistance in volts mode?

I don't need it - the Weston cell was for calibration of the meter. It uses a 1.5V or a 15V dry cell for resistance measurement.

No, the Weston cell was a stable reference cell to calibrate the meter. Uses a standard 1.5V D cell and an odd 15V dry battery for resistance - I built a 15V pack for it from 2/3N cells about five years and it's still working fine. You can get the blocky battery from various suppliers but they don't often have stock

IIRC, only 10,000 ohms per volt on DC, and very much worse on AC. So measuring sensors fed from a 5 volt rail where you might be interested in fractions of a volt will be inaccurate - when those settings are given from measurements made with a modern 10,000,000 ohm buffered input DVM.

This was realised even when these meters were the norm. Well equipped workshops would include a valve buffered volt meter for accurate measurements. But of course this required a mains supply.