In reply to rogersavery:
Thanks for the warning! It's been mentioned a couple of times (note terrifying picture posted by TobyA above) but good to have it reiterated.
I'm currently in contact with Tenbigh Army Surplus and I can't recommend them enough. They've dealt with all of my annoying questions patiently (re: age of boots, crampon compatibility, condition, use), hunted through their stock to find an otherwise sold out item and the employee I'm speaking to is a climber himself.
I can't imagine many people on here have any need of army surplus, but if you're looking for cheap B3s I'd recommend them happily.
Post edited at 16:26