Hi onetenor
If your Sanwa has black plugs it is the earlier variety, modern sets have blue plugs which do follow the standard configuration as advised by Haverlock.
The old variety had ve and signal on the outside pins with -ve on the centre pin. They will not stand reverse polarity. The plugs were also thicker than the modern type. Also the wiring did not have a red wire and had a striped black wire but I can't recall the polarity.
The official UK body on frequency control is at
http://www.ukrcc.org/index.html. Using the wrong frequency could invalidate any third party insurance you have should there be any claim for damages.
Dave