I just added the flight number in post no.1, as I checked the till receipts and they say :
Dest Code: JFK
Flight No: BA54
Thank you for your custom.....
followed by a warning that if your destination is outside the EU you may have to pay VAT when you return to the UK.
Funny thing is.... there is no BA54 to JFK (that's a JNB-LHR flight).
Two separate sales staff input the same fictitious flight number. Without even thinking about it.