The nice people at Flickr's B&W DIY group have suggested Kodak HC-110, but that was patented after Verichrome was discontinued, and, strangely, I can't find a on online supplier anywhere in the UK. (Only $12 on amazon.com, but another $60 for p&p. I should bloody cocoa). The ingredients are secret. Rodinal is also being suggested, but I don't have all the ingredients for that. So my best guess at the moment is Beutler A + B.