Cheers. Hadn't noticed your second reply on this.
We managed to book the Club Suite flight (BA281?) successfully, for next August, using two AMEX vouchers to cover the whole family. Job for tomorrow is to ring and try to add the return flights to the booking. Intention is to book those returning from New York to LHR. (LAX to JFK shorter than JFK to LHR, so should be able to add this as an open jaw).
Then have to hope Biden opens the US back up to British visitors before next summer!