BKK would be an interesting move for BA with the "densified" 777s at Gatwick, if indeed they have crew rest to facilitate it.
South Terminal re-opening will be a genuine logistical challenge. With very limited parts of the building open, it's already clear if you spend more than about 10 minutes in there that the rat population has firmly taken up residence. I shudder to think how many systems and baggage belt failures that they'll see upon re-opening given everything that must be being nibbled and chewed on a daily basis.