Should be noted that a couple of flights move early, but these early moves will be directed to the No1 South lounges until 25Jan.
From FT:
from 11 January 2017: BA2273 will depart for JFK out of the South Terminal
from 12 January 2017: BA2272 will arrive into the South Terminal from JFK
from 19 January 2017: BA Naples flights will operate in/out of the South Terminal
Customers on these flights should check in at Zone A within the South Terminal
The South terminal is much more convenient for the railway station which is just outside and the Hilton, which is just through the carpark