Hi Dan,
These are Althoff connectors. see
http://www.althoff.de/englisch/index-dialyse.htmIf you order direct from Althoff they need the money up front - not sure how easily you can set up an account
The ones I have seen are equivalent and compatible with Walther LV-004 connectors - might be best to talk to Walther as they are aleays very helpful.
I was persuaded to have the plastic male versions as the outlets fitted in the media panels. I should have stuck to my guns as they are regularly broken off, although the valve is captive so we haven't had any floods.
Regards
Chris