Personally, I'd go for Architecture (though I'm biased as I do currently study it). But architecture as a subject is incredibly broad, and with just an undergrad degree, you don't have to go into architecture as a profession - I know several people who have internships in the 'design industry' who are currently on my course. Architecture would give you the chance to go into just 'something in design', whereas product design wouldn't give you the chance to go into architecture.
Also, any reason for those three universities? Loughborough don't offer architecture, as far as I know. With architecture, there are so many courses that all have their merits - and to be honest, as long as you're on a reputable course, it doesn't really matter where you study your undergrad - it's more about the portfolio you produce to show employers than anything else.