Hi, sorry I'm replying bit late.
Just been looking at the pages of UKBA - the validity of permit you've mentioned doesn't seems right to me, because if you take a look at this link (http://www.ukba.homeoffice.gov.uk/eu...sponsibilites/), they do not mention anything about validity. So I assume that your permit will be valid as long as you and your partner are permanently staying together in UK. May I ask where did you got that information?
Are you sure you didn't got it confused with some other kind of permit (visit visa or something)?
Good luck to you![]()