The phone calls started a couple of weeks ago. At about 5.30 each evening - if I am lucky - I will be greeted by a sweet, excited voice declaring: "'Allo Annie".
Before I have quite finished my equally excited response of "Hello Edie Bear", my two-and-a-half-year-old granddaughter will have launched into a 10-minute monologue in broken English that occasionally includes a whole sentence - well, more often just a phrase - that I can understand.
The one repeated the most, and the one I love the best, is: "I want to come to Annie's house."
Because, although I wasn't aware of it when I fell in love with the country cottage I moved into a little over a year ago, I now realise that I bought it to create an Enid Blyton idyll that would be a haven for Edie.
Not just because I needed to offer my granddaughter (who, thankfully, has abbreviated "Granny" to Annie) the same happy memories I enjoyed as a child staying in my grandparents' house, or even because I wanted to emulate the wonderful way in which my own mother brought magic into my children's lives in her beautiful riverside cottage.
If I am honest, the real reason that I have turned Annie's house into Edie's second home - with a dream bedroom filled with toys and a fully equipped playground in the garden - is actually more selfish than selfless. I wanted Edie to want to be with me as much as I wanted to be with Edie.
I imagine that the Prince of Wales's decision to make a few changes to the picture-perfect grounds of his precious Highgrove might have been motivated by a similar wish: to want Prince George to be with his grandfather as much as his grandfather wanted to be with Prince George.
The renovation and upgrade of a treehouse at Highgrove and the installation of the ultimate playhouse - a 4 metre shepherd's hut on wheels with a built-in bed and wood burner - certainly suggest not just this, but that the Prince may be suffering from "competitive grandparent syndrome". Is he trying to keep up with the Middletons?
It's impossible to imagine quite how many party tricks Prince George must enjoy when he stays with Granny and Grandpa Middleton, who have the natural advantage of being maternal grandparents.
Indeed, among my own, slowly growing group of fellow grandparents, it is the paternal grannies and granddads who tend to display the most extreme examples of competitive grandparent syndrome: using their children's inheritance to attempt to buy their way into a more dominant place in their grandchildren's life - paying for everything from a private birth to a private education.
But the most dramatic turnabout that all grandparents experience is a reversal of all those strictly held rules of good parenting that you imposed on your own children.
Even men who believed in outdated notions such as "children should be seen and not heard" or "spare the rod and spoil the child" find themselves turning into a doting, indulgent Werther's Original grandpa.
In fact, men who have had demanding and successful careers that forced them to be distant fathers when their own children were young are often the most hands-on granddads. My brother, for example, once a hard-nosed news editor, now runs "Grandad Day Care" for two of his granddaughters, playing Sylvanian Families and even, on command, switching the television from a live European League title match to an episode of Peppa Pig.
For grandmothers like me, the reversal usually involves breaking the rules on eating between meals (and good nutrition in general), table manners, bedtime routine and television. This is partly because I don't have to live with the repercussions of letting Edie watch the sing-a-long edition of Frozen on a loop while eating Curly Wurlies and Monster Munch crisps, and partly my way of making sure she loves staying with me.
Because I know that most of the reasons Edie does love coming to Annie's house have little to do with seeing Annie.
Edie can't yet articulate what it is she loves about a sleepover with Annie, but her five-year-old cousin Naomi - who occasionally stays with me, too - has it all worked out: telling her parents that she has the best time with me because "there are no rules and you have cake for breakfast even when it's not your birthday".
That is, I think, a pretty good definition of the role a grandparent should play in the life of a child. And I can think of no more effective way to encourage Prince George to tell Prince Charles what I imagine he most wants to hear: "I want to come to Highgrove House."
- The Daily Telegraph, London