Hi Ralf,
That's interesting. The roller diameter of 8.51mm equates to 0.335" - spot on, and the width is quite close: 5.21mm is 0.205" vs the British chain at 4.75mm (0.1875" or 3/16"). The extra 0.46mm/0.018" width is not too bad, so the chain would probably work ok?
Cheers
Leon