Probably the best source is:
Click here
they have scads of different plugs, connectors, etc. Also, do you folks on that side of the pond have John Deere dealers (forgive my ignorance)? John Deere uses them on some of their larger tractors. The advantage to this type of a plug is that it doesn't vibrate out, like cigar plugs have the tendency to do.
Cheers,
Dave