Nigel,
I have the below. It's really just a glorified 'push-bike' spoke with the end ground down to a 'blade' type configuration. Means you can get the right type of perpendicular leverage on the chip that you can't with a screwdriver.
Simple to make I guess although I got mine (as you can see
) from Snap-on !!!!! ............make that my dealer supplied it to me with my new 748R on the card as you see here.
Guido