Sorry that I can’t really help either (but I’m going to blather on about the Saint for a couple of paragraphs anyway. Sorry.)
I found a copy of The Saint in New York in a storage closet at my grandmother’s house in the mid-1960’s (the book itself dated from the '30s), read it, and loved it. The phonetically-spelled accent of the NYC sidekick was hilariously unlike any spoken English anyone has ever heard, but it didn’t hurt my enjoyment of the adventure at all. I then read every Saint book that our local small-town library had. These were all later books, published in the 1950s and '60s. Even then, it was hard to find the earlier books in the series, but those were the ones I preferred.
If I remember correctly, Charteris published his first Saint story in the late 1920’s when he was still a teenager. In the 1960’s when I discovered him, he was still publishing occasionally, but it was usually collections of short stories. I lost interest when it seemed like the books were being co-written or ghost written.
I did find an early Saint story in huge paperback volume called The Black Lizard Big Book of Pulps which my wife gave me as a gift a couple of years back. I was amazed at how terrible the writing was. I really loved those stories back when I was a kid.