Mike, Did you get any further with this? I have a B39 and all the connections are leaking when I have a fairly full tank and the rubber “grommets” have gone soft and flexible and need replacing. Without cutting an access hatch (In my case a second hatch) they can’t be replaced with a “proper” fitting so I have to get new grommets.
Clipper say they can source the replacement assembly, including the pipe for the fuel take-off but aren’t sure about the heater take off as it was not a Bavaria fitting but a dealer fit option. If you have found a better solution I’d be interested.