My new injector loom came this morning as I was leaving for work in an enormous box filled with padding. It was hard to find down at the bottom. I've nipped home at lunchtime to swap it over and have just been out in the wind and rain doing so, with bits of leaf and twig trying to blow inside the engine. I soaked the female multiplug on the main loom with electrical contact cleaner and wedged it upside down to drain the oil out of it while I took the rocker cover off, changed the loom and put it back together. A quick test run suggests things are a lot smoother now. The gear lever doesn't wave about in time to the engine's irregular beat as I accelerate.