I own a Bickerton Mk X which is to my knowlege based on a Tern Link frame. When the initial frame failures of the Tern link became public Tern set up a webpage to check if a given serial was affected. This did of course not work for the Bickerton Mk X (as it was officially a different brand) but probably the Mk X was produced roughly at the time when the problematic frames left the factory. Therefor in June 2014 I wrote a mail to the address that was provided as official contact address on the bickerton webpage http://www.bickertonportables.co.uk/ at this time which was mark . bickerton at bickertonbikes . co . uk (obviously with an @ and w/o the spaces) asking for advice. I never got a reply... I've sent you the inquiry as to the mail-address you provided in your posting here and would be happy to get an answer on the question, even if it is three years late.