Pretty certain it will be, as they certainly wont be reducing the size of the PE cabin on the LGW/MAN 744s. If anything they will be enlarging it, and doubtful they would put J seating upstairs, this will prob stay in A-Zone in the nose.
There's not been any info yet about whether they are changing the config, plus it will take a couple of months to do each a/c as they are having V-Port fitted as well as new P/E seats, and the first one wont go in for refit until january, so pretty safe to say that when you fly in feb, PE will def be available upstairs.