Left the UK (from London Stansted, I’ve read elsewhere) in late October 1964, aged 9, on a British Eagle Britannia. Destination Singapore (RAF Changi) via Istanbul and Bombay. Pretty sure we landed at Changi, not Paya Lebar Airport.
Departed Singapore from Paya Lebar Airport, in April 1967, again on a British Eagle Britannia, this time via Colombo and Kuwait. (Transit stop switched to Kuwait owing to a sandstorm in Bahrain.) Touched down at Heathrow.
I recall seeing, from the gharry taking us from Opera Estate to Changi Junior School, British Eagle Britannias parked on RAF Changi’s Western Dispersal. This photo [http://www.singas.co.uk/changi/changi01.JPG] shows Changi Road cutting through the airfield, Western Dispersal to the right, a taxiway to the left. The road was barrier-controlled, given the occasional aircraft movement.
I also remember noticing that the Britannias were named; Luxembourg is one I clearly recall, and possibly Edinburgh too. Perhaps they were named after British Eagle’s European destinations (route map at http://www.britisheagle.net/Routes-Maps-BE-1964.html).