Right here, Robert (and Matt):
http://www.thorncycles.co.uk/forums/index.php?topic=2233.msg36225#msg36225This one is near enough as to be identical to the one that disappointed you. I'm so sorry it was a bust. Many's the time I looked at them wistfully from afar in years past (yes, they've been around since the late 1970s).
It is particularly horrible when such products hold just enough promise to tantalize...then disappoint so thoroughly after purchase. I nearly bit on buying one in the mid-1980s that required super-gluing the ends together and was perforated with holes to release any trapped water...until I realized if the holes also let water in, I was better off with an open chain!
They can be made at home cheaply with plastic electrical wire loom:
http://www.ibiketo.ca/blog/chain-cover-will-work-pinch The homegrown versions have the same flaws.
Coincidentally, I just got a call from a friend who fitted a similar type to his fixie last month. It did, indeed, trap the heavy spring rains while parked in the bike rack during the work day; his under-lubed chain rusted orange within a week. He didn't realize it till he pulled it open to see what was going on and discovered all was not well.
Best,
Dan. (...who wishes this sort of chain cover really
did work...but they seem to create more troubles than they solve)
