Thanks for posting, yes I have that book. The far right hand column of dials on the top picture is the area I am interested in. At the top right looks like a big ammeter over something else and over the third small one hidden behind the stick top. (Looks like it may be Historic Helicopters judging by the hangar.) The left hand panel does not have the plates over the Decca holes so it may not be the early version I am looking for.
The bottom picture shows the latest standard with the small ammeter bodged into the top hole and the other two plated over. Looking at a picture of the empty panel (I would post it but not allowed to post pictures), the top hole has a square cutout at 8 o'clock.