We're getting there. Can I just clarify, 'registration' means the date on the V5C? Mine is 1/3/13 yet Topix has warranty start date of 9 Jan '13.

So, when would my warranty expire?

One for Mike? 2016 BMW X3 30d SE in red
MY2013 SD4 XS Firenze Red, 19" 10 spoke contrast paint wheels, Signature Strips, Grand Black Lacquer trim, Cold Climate Pack - gone!
2007 TD4 S Stornoway Grey - gone!

That sounds untypical. My warranty is certainly down as starting on the date of registration, and I think the same is true for Iliacus. One thing to check - does your V5 say "Date of first registration"? I have known a garage to register a car in error, then reregister it before selling it on. Unethical and possibly illegal, but it has happened (and did they get into a lot of trouble about it). If not, then your garage has put the wrong date into TOPIx, and as you say, one for Mike, although you might want to take it up with the garage first.

Topix build date 9th May
v5 registered 18th May
Topix warranty 3rd June