Hi everyone, thank you Lattz for assisting with the pics, and for everyone's feedback, it's really much appreciated. Bianchigirll, cheers for this catalogue grab! It's fascinating to see the parts breakdown like that. Comparing it with the parts on mine, it seems like a lot are still the original (the shimano AT50 brakes are feeling very strong).
From what I can tell, most parts are working well: I'm going to be changing cables and housing for the rear derailleur, changing the brake pads to some more all-weather friendly options, new chain, sussing out the freewheel, BB might need replacing. As for the stem, it's a much longer replacement and not yet at it's max. Thinking it might be useful for any real long rides.
Probably the first real investments are going to be a fenders and tires for winter!
Thanks all!