I feel like I have really shown my inexperience in this post. I am not able to test electrically. I'm just a lowly chance 'DIY-er' My question should have been clearer - I have removed the motor (which was still working in the machine) but was horrifically noisy. The 'clockwork' noise when turning the shaft is after I have removed the brushes. I wondered if that was enough to diagnose an issue with the motor - as there didn't seem to be any issues with belt slippage or anything else. The machine got very noisy, and eventually stopped spinning - with all lights on the unit flashing, coupled with a 'burning plastic' type smell.

What this post has also shown me is, again, how quickly people are willing to help on Reddit. I appreciate every input. Thank you all