That sounds suspiciously early to me, especially since theres nothing here or on xda about a 3 uk build.
Most custom roms are xxelkc (poland) but the first Germany ones are rolling (xxell5).. would be interested in the build number....
My S3 is from TalkTalk buts it's on Vodafone UK network and is unbranded, no network splash screen or network bloatware. Wil I get the 4.2 upgrade anytime soon?
His build is
JZO54K.i9300xxelkc
He said he updated to JB before it was released but isn't rooted.
Could that be why?