dial light on De Vere Dicromat mk4

Hi

I just opened up my De Vere Dicromat Mk 4 to service it as it was getting still and see 2 wires going into the compartment where the dials are
there is nothing connected to them and they are just loose

what bulb is supposed to go in there
has anybody got that bit of a workshop manual or a picture of the thing

thanks

robin