[mickj]

Thanks for all your replies. I spoke to the DID importer who told me the HV3 chain is only used by Ducati (not true as Suzuki used it on one model) and that the link pin sizing was specific to that chain. Looking at the original O ring it looks to have been damaged on fit as its got crush damage in a spiral over 1/3 of it's circumference so I'm hoping it's a one off. I have managed to find a new link and will fit it when it arrives, I have all the correct tools and have fitted chains before.