HI Steve,
Thanks for the response. Cannon are made by switchcraft, so this would be the W3M - I can work with this 3 pin but as I need to convert another camera I was hoping to make them both 4 pin by acquiring two of the four pin versions. Unfortunately I can find neither the 3 or 4 pin versions and researching further I found some older posts on this forum that suggest they're no longer made.
I can machine or 3d print a housing to accept a chassis style XLR socket but was trying to keep it small and neat like these original switchcraft/Cannon sockets.