The book that I’m looking for was written sometime between the 1940’s and 1960’s (or so).  It was about a young woman who moved to live with her glamorous aunt in London.  Her aunt gave her a Pekingese puppy that she named “Peke Ah Boo”.  There was some kind of mystery having to do with the house next door and possibly a young man who turned out to be a spy?  It may have been a YA book – the copy that I had was hardcover in robin’s blue but there may have been a dust jacket at some point since I don’t remember any identifying marks on the cover.

Any help would be appreciated greatly, it’s driving me crazy!