ffutures | Looking for a Saint story

I've managed to identify the Saint story I'm looking for (previous post on Livejournal only) - it's The Inland Revenue in The Saint Versus Scotland Yard, AKA The Holy Terror - the plot of which is that Simon gets hit with a tax bill after writing a novel (which is poorly received by critics etc.) and uncovers a blackmailer while sorting out his taxes.

Unfortunately I can't find my copy of the book, so I still don't know what the Saint actually calls his novel - the book I've found this in is Butler's The Durable Desperadoes which contains this passage:

[describing Charteris and his respone to cricism of an earlier nove] To mount his attack, he rather surprisingly turns the Saint into an amateur Leslie Charteris. 'During a brief spell of virtue' it is explained, he had 'beguiled himself with the writing of a novel' - the adventures of Mario, a super-brigand of South America, which had been accepted by a publisher and 'could be purchased at any bookseller for three half-crowns'.

So, does anyone happen to have a copy of The Saint Versus Scotland Yard /The Holy Terror handy? If so, what was the title of the book, if a title is actually given at all?