I can only advise that the firm with the contract for building the Mazda original towbar is called ORIS and they are located here in Germany. I have attached the appropriate form to complete which can can be faxed to them. The firm is in the German language of course so I would initially recommend the following course of action:
(a) contact your dealer who initially fitted the towbar for their advice and if they can't be of any assistance
(b) contact ORIS and ask them what the shipping costs to the UK would be.
The form is self explanatory but if you need any help in completing it (if things get that far) then get back. I myself thought at one time that I'd lost one of the keys hence obtaining the form from my dealer. In the event though I found the key so never had recourse to use it.
Forget all that. I've done a bit more research for you and here's a link to the relevant ORIS page where full instructions and download for the form (in English) are given.
http://www.bosal-oris.com/english/[attachment deleted by admin]
