Thanks so much for the kind words, Joe. I must confess I was really pleased how it turned out. I took it for its maiden voyage today and it performed brilliantly. (Will post some pics later.)
I'd read so much about these little things online for the last few years and was desperate to have a go at making one, but finding the right pot caused me so much grief!
That would make sense re: Sonex, the area in London I finally managed to get it in has a big Pakistani community. I'd never heard of the brand before, so I don't think it's a particularly big deal over here either... But was nice and inexpensive, and more to the point, the right size!
At first, I did wonder if the Sonex was going to be tall enough - I've no idea how tall the Vasconia is - but looks like it all worked out in the end.
I hope you have some joy finding your straight-walled pot!