We don't know the departure time proposed for New York .But if it is in peak hours you can expect a delay of 45 minutes between pushback and take off which will affect the experience in economy. The SQ flight departs at 0935 from Newark a time which has less delays

The delay suits Qantas.The routes are only marginally profitable at the moment, if at all, due to the fuel price,and, in the case of London, longer routings due to war with Iran.

I query whether 6 first class seats are a better bet than having 12 extra business class seats

I presume Virgin would not be resuming flights without some indication that the current smartraveller advice of do not travel will be rescinded from June.

Is there any other location where you can board from the lounge?It was a feature at LHR when BA operated Concorde flights.