A genuine analogue stick can be made to work with a BBC Micro, as they operate on the same principle.
If you dig out the analogue port pinout from the User Guide, and look up a PC game port pinout on the internet you can see the pin translations needed.
Normally PC Game ports string the resistors between +5V and ground. On the BBC, you want VRef (which is the absolute high voltage reference for the A/D conversion) rather than the +5V supply on the port. Otherwise it should be pretty simple.
Interfacing digital sticks is a bit harder, as there seems to be some quirk of the A/D circuit that makes normal circuitry not work right. Something that is giving me a right pain in the arse at the moment.
By the way, I'm just up the country from you in Portsmouth

-- Richard