Exercise bike by JTX Fitness. Has been comfortably used by people between 6'4" (190cm) and 4'11" (150cm). Incorporates battery powered speedo and heart rate monitor - might have a couple of batteries to spare.
Resistance is adjustable by friction but it has a very heavy flywheel, visible in picture, which give it a natural feel. It has standard fittings for pedals and saddle, so they can be changed if you have particular preferences there.
It's *extremely* stable in use, but that also makes it very heavy, so it'll need a van or large estate car, and it'll take two strong people to load and unload. I'm happy to be one of those people at this end.

Exercise bike. (Oxford OX4)