Rows 11 & 12 on LGW 747's

TBS says in his comments on the Seat Ratings pages that these two rows are sometimes used for PE.
Questions:
Is this on an add-hoc basis when PE is full and UC is quiet and decided on day of travel?
What are the seats in rows 11 & 12, are they the same as the rest of the UC cabin or are they the same as the PE seats on the upperdeck?
What type of seats are generally fitted in UC on the LGW 747's, J2000 or earlier?
Reason for questions, upcoming trip to LAS booked in PE.
Bazz
Still Flying
Questions:
Is this on an add-hoc basis when PE is full and UC is quiet and decided on day of travel?
What are the seats in rows 11 & 12, are they the same as the rest of the UC cabin or are they the same as the PE seats on the upperdeck?
What type of seats are generally fitted in UC on the LGW 747's, J2000 or earlier?
Reason for questions, upcoming trip to LAS booked in PE.

Bazz
Still Flying