Nike Sale Instore. Different from the sale currently online, I was in the Oxford Street branch and many styles which are still full price online are 50% off instore.
For example, these
were about £100 (£103 or something like that) and these
(or something looking very similar- could be a Roche sole rather than a Lunar sole) were £76 down from £150.
Quite a fair amount of flyknit styles with Roche, Lunar and Free soled things, popular sale colours seemed to be green/blue, purple/blue and grey. (Not so much in black, rose-gold or soft/pale maroon though).
There were also quite a lot of sportswear/kit and the store wasn't very busy when I was there at peak time. I was told the sale had only recently started so don't wait too long if you've had your eye on something.