I finally got around to splicing in a replacement coil pack loom.
Amazing how much difference it does make, the engine and throttle response seems much smoother now.
I found my old one was pretty knackered once I'd removed the insulating tape. It's really scary making that first cut into the loom but glad I plucked up the balls to do it.
While doing this I noticed my tensioner gasket is leaking ... Dammit I only replaced it last year, another job back on the list.