I have just acquired another AVO
This one is, what I think, an AVO 8 MK1, built in 1967. The serial number is 1143.1.67 and part number 13574-80.
This AVO was given to me by my girlfriend, and belonged to her Father who does not use it anymore. The origin of this meter could well be Bristol Filton. It comes complete with a vinyl green case and test leads.
Just found a link to the exact same meter
http://www.richardsradios.co.uk/testsetno1.html