Here is a couple of snippets from "The Era", London, dating the song precisely, and also allowing a glimpse on the show business of that time, not any less tough than today:

Saturday, 30 September 1893
Advertisements & Notices
When the Old Dun Cow Caught Fire, Chorus by C. B. and H. Villiers, Verses by A. E. Ellis, Music by Geo. Le Brun, should be a good Song, shouldn't it? MR CHARLES BIGNELL is Singing the above Song Nightie at THE LONDON PAVILION and ROYAL, HOLBORN. Lawyers' Letters invited. Agents, Didcott and Co.

Saturday, 07 October 1893
WHEN THE OLD DUN COW CAUGHIT FIRE. TO THE EDITOR OF THE ERA. Sir,-Will you kindly allow me space respecting the above song? Mr Charles Bignell, in your last issue, extensively advertised same as being his property, which somewhat amuses me, considering I am the author and composer of same. I thought of the idea of The Pub on Fire on Aug. 29th, then I wrote the chorus, and took it up to Mr Bignell; but not feeling disposed (in a monetary view) to await his time bv taking two or three days to write the verses up, I went and sold the song to Mr Harry Champion the same night, and this gentleman sang the song at Greenwich on Sept. 7th. Trusting you will insert this in justice to Mr Champion, who holds my assignment, I am, faithfully yours,
HARRY WINCOTT. 19, Longville-road, Newington

Saturday, 21 October 1893
WHEN THE OLD DUN COW CAUGHT FIRE. TO THE EDITOR OF THE ERA. Sir,-I regret having to trouble you again, but Mr Ellis, by his letter in your last issue, seems to imagine that I was alluding to his integrity when giving my explanation of the above. This is not so, as I am perfectly aware that when Mr Bignell commissioned him to write the song up he was ignorant of the fact that he would be writing up verses to my idea and chorus; and, as far as going to say he can prove that Mr George Le Brunn composed the music to their work, this I don't dispute, because I know that Mr Le Brunn did do so. Mr Fred. Eplett has since written another melody, which makes No. 5 who have had a finger in the pie, but I don't wish to insinuate that either Messrs Le Brunn, Eplett, or Ellis would intentionally wrong me. As Mr Ellis knows, music hall song writers are not paid exorbitant prices for their wares, and when an author strikes upon something original, it is not pleasant to lose the advantages from it. I have witnesses both in and out of the profession to prove that I wrote this chorus, and submitted it to Mr Bignell, who took a great fancy to it. I didn't care to take two or three days to write the verses up, hence my selling same to Mr Champion. In conclusion I might add that I was told the idea of this song would be written up, but I did not think the words of my chorus would be included. Trusting I have now fully explained miself to all concerned, I am, Sir, yours faithfully
HARRY WINCOTT. 19, Longville-road, Newington

(Not a full explanation to my taste. Who exactly wrote the verses sung by Champion?)