Yes. Kipling sometimes uses “ther” when he is indicating an over-stressed definite article, typically by a rustic speaker. And it most certainly wouldn’t be “Winnie, Sir Pooh” as suggested by the new poster; Marley23 is dead right about that. (“Winnie, Lord Pooh” would be another matter…)
I still think Christopher Robin, when confronted with the uncomfortable fact that he had given a girl name to his boy bear, was twisting the narrative to put his father in the wrong, on account of he overlooked the significance of the word “ther” as it pertains to gender-to-name agreement.
Though not very many years later, Winston Churchill was affectionately called “Winnie” by his compatriots. Influenced, just possibly, by the male ursine character and his name?
I would also point out that at no point in the book is the former Edward Bear referred to as Winnie-Sir-Pooh by AA, but rather as Winnie-the-Pooh.
Even if the quoted conversation wasn’t fictional, and actually one he had with the real Christopher Robin, I’m sure he’d know his own son’s speech impediment well enough to either figure out the real meaning or ask for clarification.
I mean it’s not a case of the British accent adding an R sound to Anthea, but taking it away from panther.
To lay this puzzle to rest, it’s 14 karats of gold in a Florentine pietra dura (an art piece made of highly polished and inlaid colored stones).
Well the letters surely fit. Makes me feel justified for believing there had to be a solution.
Excellent work, cochrane! I hereby nominate you for SDMB Sainthood! 
In fact, it was our own Chessic Sense who came up with the answer.
http://boards.straightdope.com/sdmb/showpost.php?p=14806960&postcount=37
He should get the kudos.
Maybe SkipMagic should reopen that monster thread long enough to post the answer. No point in having the answer just floating around in Limbo like it is.
Agreed.
Right, it’s a case of the British person adding an R letter that they have no intention of pronouncing.
At least it means that Christopher Robin didn’t talk like Madea. Halleluyer!