The latest edition of MCV magazine states that Wii U sales in the United Kingdom rose by almost 125 percent last week, according to retailers. The dramatic sales boost was due to the launch of Monster Hunter 3 Ultimate, plus HMV slashing the price of the Wii U Premium console with Nintendo Land and ZombiU by £140.
Source
and I am too lazy to look up what UK sales were the prior week, if it is super low, then its not a huge jump, but positive none the less I guess.
Also, in the comments of the link, some are saying the increase was from MonHun alone, as the sale didn't officially start until this monday. Though some stores were unofficially offering the sale on friday. Any confirmation?
Virtually every HMV I called were offering the deal on Friday. Once the news broke of their amazing deal (and it was amazing), virtually all stores decided to just go along with it and sell them if/when there was demand.