Details here: https://www.ultramarathonrunningstore.com/UltrAspire-BIG-BRONCO-RACE-VEST-p...
Photos here: https://photos.app.goo.gl/aPq7Aja5nMLPB2PK6
In good used condition.
What size?
I can't find a label but I would've bought a medium. I'm 38" chest and sometimes just wore it with a t-shirt and with an insulated jacket under in winter. It's very adaptable.
Any takers at £45?
As used by the winner of the Moab 240 ultra trail race last year....