OK. I got game........
So answering my own question now. Yes, connecting each of those male bullet plugs into the female one for a few seconds brings up another code, then unplugging it brings yet another. 481=S, 482=H, 483=V, 484=R2, 485=B, 486=R1, and 487 doesn't do anything unless you have a 7-axis machine.
Then have to switch machine off. Turn it back on and no more E0052 error messages. Job done I believe.
However.
I now have another code that comes up just after I grab the deadman switch.
E1001 (--) PWM signal momentarily stopped.
It's "countermeasure" explanation says to replace the drive unit.
Sounds ominous. Sounds expensive.....
Any ideas anyone?
Not to worry... the error just means that you have successfully reset the encoders. Not you would have to do encoder correction and then this error would go off. What the error means is that the last known recorded position of the encoder and the current position (obviously junk value due to resetting) are so far apart that the safety system thinks there is something wrong with the drive unit.
This error has been carried forward to their new AX controller, but the AX controllers have better inbuilt support manuals which explain this phenomenon in much detail. Bad english but wonderful robots.