Hi Sea.mariner thanks for showing us the photos. The kinematic servo took me back to when I was in the Services in Germany and I bought one, this would be in 1957. I got used to using it and it takes quite a knack to get used to it.
I would not try to use it with a powerful motor unless you put a lot of protection around the model.
You are continuously bleeping the control switch with long and short pulses. The short pulses partly rotate a clutch type mechanism that goes through a sequence of fwd. - stop - rev. - stop and the rudder has to go through port before starboard. You will need nerves of steel and the reflexes of a 10 year old X-Box fan.
So one pulsed channel gives steering and motor control.
I would be surprised if the contacts on the kinematic would last long with a Taycol motor, all sparks and back EMF even if the interference can be conquered. Also check the kinematic for free movement in the clutch area.
We changed to decimal in February 1971, I remember it well as I also decided to give up smoking (Successfully) on that date as well.
I rather suspect that the value is not very great, but there cannot be many boats in the U.K. with a kinematic servo in!
I can't remember if the radio has a soldered in crystal, Otherwise you will be the only model able to operate.
But good luck with it, if it were mine (I sort of collect old RC Gear), I would either keep it as a museum piece and demonstrate the way things used to be, or strip out all the RC and drive motor and start again.
regards Roy