In order to clear up the confusion as to whether this Steelbook is being released by Studio Canal or Sony, and which disc of T2 is being utilised, I've done some research.
Carolco Pictures Inc, the producers of T2, filed for bankruptcy in 1995 and their film library was purchased the following year by Canal+, the parent company of Studio Canal. The films in that library, including T2, are owned outright by Studio Canal worldwide. It's probably the most famous and the most popular title that Studio Canal owns, so I can't see them signing away their proprietary rights to it anytime soon.
In respect of home video releases, Studio Canal directly distributes its own product in the UK, France and Germany, with the distribution rights in other territories being licensed to other companies, principally Lionsgate and Universal.
There have been previous Terminator anthologies from Sony in Europe and Warner in North America. These have included the locally released discs of T2, which have been
licensed to them specifically for release as part of the anthology. The rightsholder's proprietary rights remained otherwise unaffected and individual releases of T2 have continued to appear from the likes of Studio Canal and Lionsgate, not withstanding these anthology releases.
The artwork for the UK Steelbook, placeholder or not, is identical to that of the forthcoming German Steelbook and the already released French Slipcover, both of which are from Studio Canal. Even if Sony had somehow secured the rights to release the Steelbook in the UK, I cannot see them using the Studio Canal artwork.
It appears, therefore, that the UK Steelbook will be from Studio Canal, with Sony merely releasing the anthology.
As regards the actual T2 disc being included in the UK Steelbook, a clue is provided by the image of the rear of Studio Canal's French Slipcover (post #223 above).This details the specifications of the French disc and they are identical to those of the previous Skynet Edition disc.
Studio Canal's previous releases of the Skynet Edition in the UK, France and Germany were identical in terms of the disc's specifications, so it seems likely that the same disc will also be included in the re-releases for all three territories.
The disc contained in Sony's anthology, however, is not that disc.
@paulboland has referred to a customer review on the Amazon (UK) site in which the customer states,
"Just one note, T2 is not the Skynet Edition, this is the original Blu-ray release."
Evidence supporting that fact is provided by the image of the rear of the anthology.
View attachment 166544
Unfortunately, the image from Amazon's site is one that cannot be enlarged, but it is possible to see the Amaray artwork of the respective films included in the anthology. It is, incidentally, bang up to date with the artwork shown for T1 being that of the new MGM/Fox edition, released as recently as last week!
The artwork shown for T2, however, is not that of the Skynet Edition but that of its predecessor.
View attachment 166548
It is the artwork of the first UK Blu-ray, released by Optimum (Studio Canal) in 2008, containing only the Special Edition Cut and absolutely no extras.
If it was the Skynet Edition Blu-ray, released by Studio Canal in 2009, that was included, the artwork shown would instead have been this.
View attachment 166551
Given that only a year separated the two releases, I would imagine that Studio Canal have plenty of copies of the first one gathering dust in their warehouse and farming them off to Sony for inclusion in the anthology makes good business sense. Unless, of course, Sony specifically requested the earlier disc due to it being Region AB, to fit in with the other discs in the anthology, whereas the latter disc is Region B locked.
In any event, to sum up, it appears that there are two discs being released in the UK of T2. The first is the forthcoming Steelbook from Studio Canal which includes the previous Skynet Edition disc (2009), containing all three cuts of the movie but locked to Region B.
The second is the anthology from Sony which includes the first release disc (2008), containing only the Special Edition cut of the movie and is Region AB but contains absolutely no extras.
Unfortunately, neither disc contains the new MPEG-4 AVC encode. For that you'll need the new US Lionsgate disc (Amaray only), the new Canadian Mongrel disc (Amaray & Mondo Steelbook) or the forthcoming Japanese Ultimate Edition (Amaray + Slipcover only).