Do you mean your starter motor engaged with your flywheel ring gear?
If so, as you say, you need to look for damage at the ring gear. Why do you need an alternative flywheel? New starter and fresh ring gear from usual Lotus suppliers, when required. I would have thought the starter would be damaged and the ring gear well marked up. Can you not take the starter out first and turn the engine over and look from below (with a torch) to see the ring gear teeth, first.
I would be concerned with your wiring and how your starter got it’s signal to pull in.