Found these in Brentford/Isleworth branch of PC World / Currys. They were award winners in 2012 and 2013 with What Hifi (apparently). There was one on the shelf, but I didn't have time to ask if there were any more.
Currently retailing on Amazon for £100+ and there are a few pairs from random sellers on eBay for £80+
I am under no illusions that this might be a one-off and that I got seriously lucky, but wanted to give people a heads-up if they're heading to their local branch to have a look.
Snippet of the 5* What-Hifi review:
"Philips Fidelio M1: Sound quality
It’s a rounded, refined presentation. Vocals are given room to breathe, while high-frequency sounds are natural and don’t harden up when you crank the volume.
Stereo imaging is impressive too, with instruments sitting explicitly in their own space; it might not be the widest soundstage you’ll ever hear, but it’s tightly marshalled.
Downstairs, the bass is weighty, although some might prefer a touch more punch. It never overwhelms proceedings, stays nice and tight even with complex rhythms.
The M1s don’t grab you by the lapels and force you to listen. But in our view that’s no bad thing – they may not be the most exciting listen, but they excel over long listening sessions and won't wear you out."
Good luck, hope someone somewhere can bag a pair of these.