I had a similar experience in my childhood, Bluebelle. My father was in the army and six years of mine and my sisters childhood was spent in the Far East.
My maternal grandmother lived with us for the first four years of my life as her house was destroyed in the Blitz, she only moved out when her house was rebuilt. Then her grandchildren were whipped away and we didn't see her for three years.
She died just a fortnight after my parents headed east for the second time. When my mother parted from her for that posting she knew it was probably the last time she would see her mother alive. She had not, however, expected it so soon. My grandmother slipped on an icy pavement a few days after her departure and died of her injuries. My mother was not an only child, but we were the only grandchildren.
As you say, the only means of communication was airletters and the occasional parcel.
Even when we were in England, we lived in Carlisle then north Yorkshire so visits south or her finding the fare to travel north limited visits to only about 3 a year.
I also stayed with her for a week or two on a couple of occasions. I absolutely adored her and was devastated when she died.
People eating and drinking on the go