PE seat reservations on Upper Deck (bubble)?

I've just upgraded to PE for my flight from LHR to SFO and back. I've logged into my booking to select my seats and it's not showing any availability on the upper deck even though it's 10 months away! I know that not all the seats are released straight away but will more PE seats in the bubble be released nearer the time? I just want to know the best way to secure them if I can.

[Neil]

The LHR 747's that operate the SFO flights do not have any PE seats in the bubble, they are only downstairs.

The Bubble on the LHR 747's are a mixture of UC and Economy.

Thanks,
Neil