Thanks for your reply. You are correct to say that the watermota “Shrimp” would be too small for an Atalanta. The system fitted to some Atalantas (such as A17 Gambol) was much more robust. Of course I have forgotten the makers name.
Incidentally Dinah and I had a “shrimp” in a “Mistic” when we were young. It was not very reliable and certainly in poor condition when we got it.