There's a fantastic old hardware store just near me. It has no Internet presence, but I just stumbled across a Facebook video the BBC made a couple of years ago. The most obscure thing I've bought from there are replacement gas mantles for a 1910 gas lamp. When I asked, somewhat jokingly, they came out with 3 boxes of different sizes and one matched the holder perfectly.
Sorry it's a Facebook link, but I thought it was worth sharing...