Ah, now I understand !
The item at No.12 is the tailplane incidence indicator, and is nowhere near the handle at No.11.
The incidence indicator is like a small bubble level, with a '+' and '-' mark fore and aft, and shows the angle of the tailplane, which could be adjusted in angle of attack by the round pulley wheel. The handle at No. 11 is the seat height adjuster.
I should have a clear pic and drawing of the incidence indicator, which is mounted on the lower port wall, which I'll post here later.
NOTE. The incidence indicator appears to be missing in the colour pic with the transparent fuselage section, and also, the throttle lever handle is non-standard for the 'E' version, being more like the 'F' series onwards. On the 'E', it was normally a 'ball' type handle, yellow (for fuel) with a thin red stripe running centrally fore and aft.