Attached is a pic of the WS19 Power Switch Unit from the inside of Bovington's Sherman Firefly... item to the right of the Variometer.
I am assuming that this is the master on/off switch for the WS19 supplying the feed from the tank to the WS19 PSU.
Does anyone have one of these switch boxes (assuming with a meter underneath) which they would either be happy to sell me - or at worst, send me some better pictures and info about.
Unfortunately I do not have a colour version of this picture... the original of which this is a small extract was supplied to me by Bovington Tank Museum and is their copyright.
Many thanks
Tim