I mentioned last week that -- until I got side-tracked -- I intended to discuss some ideas put forward by Christopher de Hamel in the Introduction to the Burke Collection catalogue.
I received a copy of the Burke catalogue on 11 February, less than a week after its official 5 February publication-date, and by a curious coincidence of timing this was just four days after I wrote a blogpost about possible collaboration between Ottley and Celotti when selling illuminated cuttings, a subject addressed in the Introduction.
Christopher knows as well as anyone that what is not said in a dealer or auction catalogue is often as important as what is said, and is in a strong position to read between the lines. In particular, he points out that the title of the famous 1825 auction catalogue of Celotti illuminations sold at Christie's, does not say that Celotti was their owner, only (in the "fine print") that he had collected them and brought them to England:
"The catalogue was written entirely by Ottley, who signed the introduction with his initials. [...] The named involvement of Ottley in the sale catalogue, unusual enough, probably conceals a closer involvement with the consignment than is at first apparent.  [...] He had probably bought some of Celotti's offerings already.  It is even conceivable that Ottley had acquired the entire Celotti collection en bloc some years earlier, and had weeded out what he wanted before sending the rest to Christie's under the previous owner's name".
This last suggestion is not stated as a fact, or even as a probability, only that it is "conceivable", which it certainly is. But I am inclined to disbelieve it. Mainly because the auction of cuttings, held at Christie's on 26 May 1825, took place in the same auction season as a sale of medieval manuscript codices, held at Sotheby's on 14 March 1825, which states unambiguously on its title-page that it consists of "the property of the Abbé Celotti":
It is possible that Ottley was selling a huge collection of ex-Celotti illuminations at almost exactly the same time that Celotti himself was selling medieval manuscripts, but it seems to me much more likely that Celotti was the vendor at both auctions.
While on the subject of the 1825 auction of Celotti codices, it may be worth mentioning that its title-page mentions several provenances, including "St. Michele di Muvano [sic]", and yet the descriptions within the catalogue make no mention of any manuscript being from San Michele (or San Mattia) di Murano:
This is despite the fact that other former libraries are cited with some frequency in the descriptions, e.g. here:
 I came to the same conclusion in the post in February.
 We now know that this is certianly true, as discussed in the same post.