You dont need to modify the dizzy itself at all mate.

At the moment your ignition works by:

Ignition module -> Coil -> Dizzy

Instead of the ignition module triggering the coil, you get the ECU to do it instead. Not sure on yours if its points or electronic, but same applies either way really.

I'll happily help you with the mapping if you go down that route, looks like comedy so Im sure it will be a good laugh anyway, me and Tank Mike are round as far as Junction 25 of the M25 relatively often anyway, so not too much extra hassle to pop up to yours one evening for a late mapping session