This meter was being produced in Newark around 1970 until mid 1974.
In the UK it was being made by Sangamo Weston in Enfield until 1980 when a former manager at Sangamo Weston, John Gahagan, set up East Kilbride Instruments to continue manufacture but without the Weston name. Manufacturing continued until July 1984 when that company went into liquidation
Manufacturing was continued by Megatron, initially using parts from East Kilbride until October 1985 when the Euromaster 2 was introduced.
The picture shows model S461-6 serial 5999 0 manufactured at Enfield. This was purchased from a boot fair in Essex for £4.00 boxed as new with instructions, leather case and invercone.