Alfred,
Happy New Year!
First of all: thank you very much for digging into this!
It makes me feel less guilty that I was bothering people for a minor detail - but we have the full story now!
It just was lacking logic to me that a fairly long and fragile pipe is not held in place by anything - so I asked. I lost hope after the first few posts and then Cees gave it a new spark! (thank you Cees!).
On the pictures: the 49er picture and one I attached looked similar at a glance, I was not paying attention to the brake booster - true. And I was missing, I think, the picture of the Holy Grail's engine from left side...
I am also happy to hear that my "size matters" theory is sort of confirmed - clamp for a longer pipe.
As for part numbers:
1. EPC/Webparts do not recognize the number you quoted (A1879950063)
2. What EPC says (and what I think I can see in your book) is clamp number A1879950037 (this is the one I quoted in my post above). Webparts says it is not available - I asked a question to the dealer. If it is not available, I will kindly request a favour from Cees, maybe he has one...
The million dollar question to me is: what is the bracket I need?
I will see if I can fit the one I ordered.... maybe it is this one - that's my story and I'm sticking to it!