According to VGChartz, Halo 4 sold 48,959 copies in the UK in the week ending 1st Dec. If this article is right, and Halo 4's sales increased 36% this week to 52,340, then that means that last week it sold 38,485 copies.
Basically, VGChartz overtracked Halo 4 by 10,474 copies in the UK this week. Disappointing. :(
My prediction threads:
Wii U will sell under 40m units (made on 14th September 2012)
PS Vita will sell under 20m units (made on 30th September 2012)
Wii U will sell under 7m in 2013 - I was right