Only just seen this 6 months after it started.
Eagle's first Britannia came in 1960, and they had three, later two, in the fleet through 1961. They also had four DC-6s in the fleet as well, and both types operated the MoD charters which in those days made up a lot of their workload. Does the original poster remember whether the engines were smooth turbines or hammered away all night ?
According to Tony Merton-Jones' book (invaluable aid for such questions) these charters were operated principally out of Heathrow and Gatwick, rather than from military bases. Their range meant that stops at Istanbul and somewhere in India were common.
Stories of desperately poor food provision on these flights (and multiple accounts of food poisoning en-route) are a recurring item in such accounts, and seem to be brought about by the MoD of the time driving the charter prices down and down as far as they could manage. Of course, the civil servants in question from Procurement, if they needed to actually go to Singapore, would be on BOAC from Heathrow with proper provisioning. It's surprising you were not issued rations; maybe those would have been more expensive.