Yeah it was bought from myprotein. I've not had the promised email containing the returns address or a returns 'sample number' yet..
The sticker on the bag puts the manufacturing date as 18th May 2011 and the batch no as 6773.
Thanks for the heads up on other suppliers. Thatt Biotest stuff looks reasonably priced so I'll give them a shot if myprotein don't offer an exchange after their 'testing'.