Ekco TS105.

[Murphyv310]

Uses an SP61 pentode, a valve that in 1949 might have been considered old fashioned but it's likely there was thousands of these valves on surplus market, so why not use the things up?

A couple of weeks later, Mullard received an order from a different branch of the services for a large number of EF50s, so the batch he'd bought were resprayed in the appropriate colour, re-stamped and sold back to the government at a substantial profit!

Things never change then Terry. This still goes on in other ways, procurement for the NHS for example.