Just picked up this thread (thank you Twitter!) and am in tune with all the thoughts posted here, there are so many of us with our children and grandchildren overseas or miles away in the UK. Forthunately my 2 sons and their families live only 45 miles away so we do see each other quite often, but before my move to Northumberland we only lived a couple of miles away so there was much more contact then.
My DD emigrated to NZ with her husband and baby of 4 months in 2006 and words can't describe how much I miss her and my two grand-daughters. When her husband was offered a job in NZ she asked me my view on them going to live over there (they'd already had a holiday out there to see what they thought of the country, they loved it!). She was worried about leaving me and how much we would miss each other. My response was they had to do what was right for their family and their future, that I was behind them 100% and if I had had the opportunity when I was their age I would have gone for it.
It sounds as if I made the perfect response, which I think I did, but the thought of them being away on the other side of the world was horrendous.
They had another baby born out there, who was born with a health problem (thanks to a wonderful surgeon she fully recovered) and I made a mercy dash which took 3 days door to door. I have visited every year since they went and last year my DD was diagnosed with MS whilst I was out there (a shock to us all as she'd had no prior symptoms) and it was so, so fortunate that I was there at the time and able give lots of love and support, but my, it was difficult to come back home after that visit!
Basically that is the real problem for me, the enormous distance when things go wrong, plus the emotional goodbyes. But . . . they are having a fabulous life out there, are very, very happy and I get to spend 6 weeks every year with them and really getting to know my 2 GDs.