That is a coincidence, John!

The Virgin Classics disc is indeed from 1992 and, from the liner notes, says that they used a new edition prepared from the autograph score in Stockholm, so that could be why it's referred to as a 'first recording'. The Rumstadt recording you have appears to have been released in 1986 from what I can find online. It's an interesting 'work' in that it isn't really an opera, or indeed a singspiel; it's described as a 'drama with song', which seems more apt: Act I's music consists of two arias (for Delia); Act II includes a very brief chorus, an aria for Roxelane, an intermezzo, Elmire's Dance and a duet for Delia and Roxelane. It's Act III where most of the music comes (41 mins on this CD) including marches and ballet with suitably exotic 'Turkish percussion' which was so fashionable at the time.

Incidentally, I first came across some of the music on this very entertaining disc:

with Concerto Köln and Sarband joining forces in music inspired by the East, such as Mozart's Entführung Overture, Gluck's La Recontre imprevue, Süßmayr's Sinfonia turchesca , an exotic Concerto turco by Marquis De Ferriol and other Turkish delights.  

And one in particular, as you know, just happens to be one of the finest tunes there is...

from an online catalogue (http://www.bookmaps.de/lib/ruc/s/o/sol_31.html)

Soliman II.: oder die drei Sultaninnen
Kraus, Joseph M. ; Simons, Yvette ; Kirchner, Eva ; Kiefer, Volker ; Barth, Walter ; Rumstadt, Guido J.
Hardheim. Pan-Vleugels. ca. 1986. 1 Schallpl. : 33 UpM, stereo ; 30 cm.

There was a kind-of "tradition" in Singspiels and other sung/spoken pieces that the main male character would be a spoken role, and often would not say much until towards the end (when he would traditionally come on and "explain" what had happened, etc).   In part it was a dramatic convention, but it was also about good box-office - it gave theatres a chance to put a box-office "draw" actor into a musical piece, and get both "music" and "theatre" audiences along to the same piece    SERAGLIO and SCHAUSPIELDIREKTOR both exhibit this tradition.  Storace picked-up this ball and ran with it in London - all his main opera pieces have a spoken "heroic" male lead, with the tenor lead usually playing the anti-hero. THE SIEGE OF BELGRADE (1791) is another of these "Turkish" pieces.. the Turkish Field-Marshall, the Seraskier, is a tenor, while his Austrian opponent, Colonel Cohenburg, is a spoken part.