I don't know of the part number, I have recently talked to Harold Wood and it sounds like they have a very limited supply and I know he wouldn't sell any.
I am making some connectors. It's not easy, probably the most difficult ones I have had to make because the pins are so close together. the grip switch is not a problem. I just tuned a piece of plastic in the lathe to get the correct diameter and then drilled the two holes for the female pin recievers. I use plastic called P-tex for this. It's hard enough to drill and it can be easily molded and glued with heat. I think a regular heat gun and glue would work well too.
I am now waiting for the pin config before I start on the data output cable. I need to see how many pins are actually used.