Seems like the UK PSN Store can only update on a Thursday, as the PSN download for Warhawk has been delayed two days until next Thursday.
Threespeech: We have just received information that the next PS Store update, which will contain Warhawk, will be Thursday 30th August and not Tuesday 28th August as previously announced. As you know Thursday is the usual day for our PS Store refresh. We are sorry for any inconvenience that the extra 48 hours wait may cause.
See you there!