What aviation fuel did Virgin Atlantic use on it's return flight from New York to London Heathrow on 28th-29th November 2023?

On November 28, 2023 Virgin Atlantic used 100% sustainable aviation fuel to fly a Boeing 787 with Rolls-Royce Trent 1000 engines, from London Heathrow to New York JFK airports.

The SAF was a dual blend of 88% HEFA and 12% SAK .

No mention was made in the news articles concerning what jet fuel (including possible engine adjustments) were used on the return trip from New York back to London!

For example were the fuel tanks on the aircraft completely flushed out before refilling with regular JET A .

Peter Brooks

Palm Bay FL