The time on my mobile telephone is not the same as the pips on BBC R4. The network time seems to be about 60-90 seconds behind the BBC which I have always assumed is what is used to set atomic clocks.
Not sure if you really think the atomic clocks run to the BBC R4 pips or not but amusing if you do......
Interesting thing is if you try listenting to Radio 4 on a FM radio, a DAB radio and then say over cable/satellite - you will find that they are all out of sync with each other by a few seconds (not as much as 90 tho) and FM will be the one ahead - this is all due to the time taken to transcode the signal, broadcast and then decode the signal - with better equipment the delay will be less but for something such as satellite you still will have the transmission delay up to and down from the satellite on top of the digital/analogue conversions.
On a DAB radio usually you will get the time source on the radio picked up from the transmitters - if you listen to radio 4 and watch the time tick over and listen to the pips you will probably find the radio does it before R4.
Sorry no real input on your issue BOAC - just amused at atomic clocks being set by the pips from BBC, bought a smile to me at the end of an otherwise dull day....
Merry xmas all....