Spares came today, so spent most of my day off tinkering.
Firstly had to open up my 12 key set to figure out how to rewire it, so that done, I had to fit the buzzer.
Then the GPO grommet on the line wouldn't fit through the screw in hole through the back, as all Dictographs have differing sized apertures on the back of the sets depending on how thick the bunched cables are for all the outstations, this was too small.
So cut the retaining grommet off and tied the cable in a knot and its a fine cord restraint.
The handset cord retainer at the TX end was non-existant and 4 wires were hanging out the bum of it, so opened it up, and figured out I might be able to use the now sliced GPO grommet to poke a tail through and make it secure.
Anyway I had to re-strip the grommet back about 5mm to get it snug in the handset handle cord outlet and completely rewire the handset and after much pushing, shoving and brute force the handset went back together again with a nice new rubber tail on the end, this took longer than the rewire and adding the buzzer.
Great value though, buy one GPO line cord and wire up a set AND repair the handset line!
Now the dial, its not connected at the moment , but is sticking, you dial "1' and its doesn't return, you dial "0" and it it sometimes returns and makes a four loud clunks when doing so, guess the governer needs cleaned.
So it buzzes and you can talk on it, but have haven't done anything to clean it up yet.
Actually the whole handset reminds me of a slightly enlarged 500 one, similar spring contacts, held down by the pressure of the caps.