Just keeping it real.
Perhaps these UK sales are not indicative of wider trends (God of War did 80-90k at UK launch but went on to sell over 3.1m world wide in its first 3 days), or perhaps the digital split was particularly high, but in truth I can't imagine this being the case, and can instead see a scenario where a quirky title like this appeals less to the American market than the European one, which would make it fall on Japan to bridge the difference.
I guess we'll know more soon enough, but it's possible the reviews (especially from IGN) had a somewhat negative impact on sales, as if this UK result ends up being indicative of a wider sales trend, would make this the first Sony exclusive that's out of sync in sales comparative to its social media pre-release view metrics.