So, was scrubbing away with a steel brush... and I noticed a speck of light in the cover.

Well, that's no time to let up so I scrubbed harder. It was a weak spot right in line with the thermostat bypass hole... had plenty of crud caked in there.



Almost thought it was a bad thing... but I'm pretty happy I found it now, rather than powering up a mountain in a cloud of steam...

So... not finding any covers online, and the complete housings on feebay don't look too good...