Any info on Tester TMS No1 (WY2521)?

[greenstar]

I have been given by a generous friend the aforesaid unit, marked in full 'WY2521 Unit Oscillator C.F. No1. Tester T.M.S. No1 Mk II'. This example lacks the front lid that usually contains the circuit diagram, and three capacitors have been harvested from under the chassis. I have the outer case.
Googling gave me a fuzzy circuit diagram without component values, and the knowledge it is made for testing telephone lines. It looks to be a rather nice AF generator.
What I need for it:
Values of the missing caps (I have the one in front from the attached photo)
Clearer circuit if poss.
The power requirements (seperate power unit) - looks straightforward, although there appear to be two HT voltages.
To know what type the big panel connector is, and to find one.
It's a nicely built thing. I have a weakness for signal generators.
Tony