Curious to see that plocky45 posted his comment only yesterday as today, while trawling through my old copies of "Blues & Soul", I reached the edition (B&S #903 - 30th Sep 2003) in which this was advertised as a new release available at HMV (images #1627589 and 1627597).
The adverts give the release date as 29th Sep 2003 and it seems that the whiz-kids compiling one of the ads had the same dilemna as I did when deciding what to put as the image for this release and used their own version of smoke and mirrors to come up with something that combined the covers of the two CDs .... and very nice it is too. The other advert uses the "Speakerboxxx" cover, which is something that supports what plocky45 comments about the Speakerboxxx cover normally being used as the primary packaging for this.
As RogerFoster comments this is, conceptually, two separate CDs.
For packaging purposes, one has to come first. I only ever see the Speakerboxxx album listed first, and I think this is supported by the packaging. The front booklet is on the Speakerbooxxx stickered side; the rear cover with barcode is on the The Love Below stickered side; the MOBO Awards sticker is also on the Speakerboxxx stickered side.
If reversing the track listing is too time consuming (and it's probably not absolutely necessary in this case), perhaps the album title can simply be reversed: Speakerboxxx / The Love Below
Conceptually this is two separate CDs in one double-hinged Jewel Case, though there is just the one Booklet (the front cover of which doubles as the "cover" of Speakerboxxx as it slides neatly into the Jewel Case). The "Cover" of each CD is completed by having a sticker on the outside of the case.
The booklet has 24 pages, half of which are for each CD, and has lyrics etc. etc.
I wasn't sure what would be the most appropriate primary image for this, so through a combination of smoke, mirrors and other general piggery-jokery I concocted an image that combines the two sides of the release as it would be seen on the shelves in a shop!!