You used to be able to buy ex-team kit direct off the BC website, I've had chainrings and 1" carbon track forks from there myself. There were surplus skinsuits etc. available too.
It will probably be the Pinarello bikes they had to get rid of after Cervelo sponsorship not the UKSI track bikes
Lolz. It's just getting worse and worse for BC - http://www.bbc.co.uk/sport/cycling/36157878
Flogging Olympic kit for profit is not allowed, apparently?
Edit - appears they were selling it on Ebay including £10 grand bikes bought with lottery money.
http://www.dailymail.co.uk/sport/sportsnews/article-3562231/Wheels-come-British-Cycling-Shane-Sutton-steps-stars-reveal-sport-s-toxic-culture.html