John,
The plug is a round multi-pin … it fits the connector shown on the ebay item I posted earlier.
Sorry folks: I think I might be wasting everyone's time …
There is a block diagram of the control electronics on the patent drawing [linked in my opening post] but no details.
… I was hoping that someone had a circuit diagram, or a photo, that would help me decide if an Arduino-based controller was feasible. With hindsight, it may be best to wait for a bargain ESP-5 box to turn-up somehere.
MichaelG.
.
Edit: This video is the most informative I have found so far.
Edited By Michael Gilligan on 08/04/2016 18:11:02
Edited By Michael Gilligan on 08/04/2016 18:21:13