I don't think the Queen of Hearts was an actual place: cafe, pub, or whatever. Surely derived from the nursery rhyme,

The Queen of Hearts, she made some tarts,
All on a summer's day,
The Knave of Hearts, he stole those tarts,
And took them clean away.

Queen of Hearts = "beautiful woman" (Queen Elizabeth I was the original "Queen of Hearts": more recently, Princess Diana).

Hilda Moriarty, the subject of the song, married another man in August 1947, the year after after "Raglan" was published.

Big Tim.