Thanks for the article, FemtoMetre. It's always an adventure! I'm not going to repaint this Mercian, as I like its antique appearance too much. It is a 55cm, which is 2-3cm too large for me, so I am building it as an upright bike.
chris667, it rides beautifully... like nothing else I've ever tried. (I had the chance to use it quite a bit when it still belonged to the previous owner. He had it set up as a single-speed beater/utility bike.)