Does anyone know of a UK source for quality pan and tilt bipods?
Bipod for a rifle.You don't say the intended use. There are all sorts of tripods, and you can just buy the heads, with PTZ and even fluid damping for tracking shots on movie film or video.
Small, light weight tripods are available from Sony, Manfrotto, Panasonic, and other makers. If you are going to swap what you mount, look into one with a QD slot, so that you can mount the matching QD plate on your camera, spotting scope, large binoculars, etc.
Go look at Amazon, OpticsPlanet, Cameraland, and SWFA to get an idea.
But I have picked up some nice tripods at thrift shops and garage sales, for a fraction of new cost.