Britannia indeed ... flying CCF/ATC cadets to RCAF Merville and USAFB Rhein-Main on the first legs of our 1963 International Air Cadet Exchange. Thank you, XL659 ... and XN398 for the inbound some 4 weeks later. Interesting that they used London Airport (Heathrow) - I presume to make it easier for the cadets to get to than somewhere in the wilds of Oxfordshire!