Thanks for the details about the resonator - I was going to look further into that but thanks to you I no longer need to! I had considered taking apart an old mouse (I have more old mice then I care to count!) and use the controller from that - I guess it should work in the same way that the MouseWarrior works! At the end of the day, if it doesn't work then I haven't lost any money - it's not as though I have any other use for out of date mice!
I really do appreciate all the help!
Martin