Sounds like you've had a good day of rewarding tasks on the wee beastie Phil!
I think i'd be inclined to wrap the new ignition amplifier module in some bubblewrap and keep it with a tube of heatsink paste and the necesary tools in the car somewhere - it's one of those things that if it ain't broke, don't fix it! Just clean the back of the existing one and put some fresh heatsink compound/paste on it and refit and it should give you many more miles yet. They usually either work or not, no in between although an overheating ignition amp can give misfires at higher rpm and once in a blue moo at idle.
That split hose between the inlet manifold and the flame trap was probably causing a lot of the lumpy idle, did you check the stub on the inlet manifold was clean through the inside?
After that the dizzy cap although probably a 50/50 split between those two!
Might pay to remove fuse #1 (i think it's #1) for the ECU memory to reset the "strange" fuel trims it will have learned and give it a chance to re-learn from scratch on the new bits that are working well.
