Never ending story.
I changed yesterday the speedos and after a short drive it was clear exactly the same failure

Talk to my dealer- dealer talked to the factory - dealer called me.
"Oh we are so sorry all speedos needs to be reflashed, could you please confirm that there is green dot on your speedo?"
My comment: "There is no green dot but my head is getting red"
It seems that the factory has again sent wrong speedos and for that reason we are doing now the same procedure again.
Speedo is on its way to the UK, will be (hopefully) reflashed and sent back.
I have the feeling that I have been arrived in the Morgan-family now.
Torsten