OK, so I've researched every single recitation in this thread, and I have not been able to find information that attributes even one of these recitations to anyone other that Stanley Holloway. Not one. I expect that further research will prove otherwise, but no far none of the naysayers have come up with any evidence that any of these recitations come from other authors.
I suspect that http://www.monologues.co.uk is inaccurate in its attribution of so many monologues to Stanley Holloway, but I'm not going to contradict them until I have solid, printed evidence.
It's clear that Marriott Edgar wrote the first "The Lion and Albert" monologue, but I can't find evidence about the authorship of the many sequels. And as far as I can tell, Holloway wrote the words to the Sam Small monologues. More research is required before we stake a claim on anything.
-Joe Offer-