"However, Rob disclaims that he has the CustomizeGoogle Firefox extension turned on... does anyone know if this extension might be causing this instead of this actually being Google’s output?"

Why doesn't he turn it off and see?

I saw this posted here a while back, I like it.

I couldn't replicate this result with CustomizeGoogle turned on or off so as far as I can tell it's one of those tests Google occasionally slips into (then out of) the SERPs.

maybe it is because the url generate the clear and functional path, so every level in URL has it's own page. So it does not mean that it understand breadcrumb in any way, it just understand the web structure (what he definitely has to, if he wants to offer good results).
BTW i like it – easy solution to offer e.g. four diferent pages, very relevant to what you search (the best fit page, it's parents and homepage) in the same space. I love such simple solutions

No, it actually understands breadcrumbs and that's obvious if you check the search results:
http://www.google.com/search?q=motability

"> Renault Cars > Renault Motability" – this text is not derived from the page's address

I like the change but it's not reflecting to all the searched site where breadcrumb is used.

It's difficult to know this change is because of :

a)Google new way of showing search results
b)Due to browser compatibility.
c)Extracting from Title Tag or Breadcrumb used in the website as a part of SEO.

[URL around "SEO" removed]