The two Brixton gigs are now available for download purchase in CD (WAV) quality:
http://www.underworldlive.com/shop/digital-audio.html
They are being fulfilled through Live Here Now's servers, rather than through underworldlive.com.
They cost £12 each, instead of the originally announced £10; however, they also come with "an exclusive poster designed by John Warwicker." I assume this is not a physical poster you receive, but rather a digital one included with the download, most likely of the album artwork.