Telemus: Last week I did a little search and now it is time to trash my notes or to to post a few observations here. 'Few' is maybe the wrong word, because it is getting a long post, and I hate long posts very much. But I hope it is partly funny, too. Let's go.
<About the new Erkel vs Szen game>
I briefly checked Whitehead's db for the game, because a newspaper of 1893 as source for a game from 1853 can give some surprises. And I was not disappointed, quite the contrary!
Whitehead gave the year 1856. With this year as a hint I found it in "Schachzeitung" (DSZ), January 1857, p 23. No date, unfortunately. The game belongs there to a couple of games which were recently submitted by a Dr. Recsi from Pesth (see p 19). But were the recently played, too? (Szen died that month, but the obituary games appeared later in 1857.)
Was DSZ Whitehead's source? The game is no. 04283 in his db, and no. 989 in DSZ. The games Wh 04281-04285 appear in the same order as DSZ 987-991 (compared only by player names, results and number of moves). Preliminary working hypothesis: Whitehead used DSZ for the game, and estimated 1856 from the publishing date.
But DSZ adds also some uncertainty to that game! There the final move is 28.♖xd6 (instead of 28.♔f1 in Wh's db and "Allgemeine Sport-Zeitung"). This move would be a heavy blunder and would lose by mate. Therefore, already the editor asked the correspondent for a correction. But I didn't find it. (Found only a correction of Wh 04285/DSZ 991 on page 70). Break.
What about Hungarian sources? There is a book "A sakkjáték tankönyve [...]" by István Márki (Gyula, 1872, see https://books.google.com/books?id=W...). Not just a primary source, but at least it has 28.♔f1 (see page 273). And one line below it states "(Pest, 1855)". Every source adds some ambiguity!
Of course, I leave it to the experts to decide about the 28th move and the year. And while they're at it, maybe they could explain to me, if the final phrases mean that the game ended immediately or continued for some moves. Thanks in advance.