The plug you need is available from many places - I have linked the parts required all available from GPE below.
I would be happy to post you a plug but it would probably take over a month to arrive.
5 pin housing:
https://www.greatplainselectronics.com/proddetail.asp?prod=CP100-05-LR
Pins (4 x reqd):
https://www.greatplainselectronics.com/proddetail.asp?prod=08-52-0123
Polarising pin (not really needed but nice):
https://www.greatplainselectronics.com/proddetail.asp?prod=15-04-9209