Thought I’d post an update: bike nerd sightseeing has been very much restricted to ‘look with your eyes’ since a broken arm has kept him off the bike (until Thursday, when he went full-messenger on a Brompton in London, in an effort to catch a train. To the many pedestrians of London, we are both very sorry).
However, ‘look with your eyes’ went very well thanks to @mary-hinge who is definitely not an axe murderer, and not only did not kill or torture us, but in fact proved to be an amazing host. Not only did he (and Mrs Hinge) put us up for the night, make us good coffee, provide entertaining conversation and take us out on the town, but he also arranged a very fine tour of the National Cycle Museum. Also, this kind of thing is what I love best about the Forum. That and the puns.
The NCM is confirmed bike nerd heaven. You should all go. Maybe leave your families behind, just go and nerd out in your own time at your own pace. We also found a bike recycling place in Newtown, a few good old bikes in the rafters of All Terrain Cycles in Shipley, a jumble of intrigue in Ellis Briggs, gritty smiles at Revs, and apparently we have to go back to London because it’s much more interesting to a bike nerd than many cities. Thanks to all for the suggestions and especially to @Mary_hinge for the hospitality.