I have a little problem with my bike, so can't ride it this week. My last spin saw the starter really struggle to fire the bike up. The symptoms were similar to a low state of battery charge struggling to turn the bike over. However, the battery's fairly recent so shouldn't be the cause of the problem. I rocked the bike back and forth whilst in gear and then it fired up, so i'm guessing it might be the magnets breaking loose or the brushes wearing down. If it's not that, then it may be the Hall Sensor, but my experience of those is that they give up instantly and not over a period of time. I've ordered a new starter, which won't arrive in time for me to fit it, so i'm bike-less this week.
I can meet up for coffee and cake, but given the current forecast, am equally happy to rearrange once i've received my new starter and fitted it.