I'd speak directly to Mazda UK, from what I've seen on the MX5 forums they are very good at getting specific information like this (on MX5 nutz various people have had them get info and paperwork for JDM spec imported 'Eunos' roadsters, sometimes they need specific documentation in order to register them in other EU countries and so on, not everywhere is is relaxed as the UK about imports and some countries will struggle to understand how a JDM model car gets imported to Britain but then somebody else wants to import and register it properly in yet another country...now we're talking 20+ year old cars that were grey imports, Mazda could have quite easily said jog on, too much hassle and too long ago....but no, they have obtained information and paperwork via Mazda Japan even for these sorts of obscure cases).