RAF Mk II* gunsight electrical question.

Hi all,

Does anyone happen to know the number of amps drawn by the bulb in a MKII* reflector gunsight? The bulb is marked 12V, but no amps.

The serial number ends in a /40 – does this make it a 1940 build date?

Its got the later style square glass, which i guess gets it the MK II* on the data plate, but i though those were made in 1941?

thanks chaps