Thanks, I've edited the post and uploaded them individually, and it seems to have done the trick.
Yeah I think what I found was that it became something fun to work on as a break from revision and study for other subjects, so I just kept at it for far too long.
Thanks!
1 & 2 make a lot of sense - retrospectively I can see those both being issues and I suppose just things that'll come with more practice and my looking out for them more/paying more attention. I did realise that the low C would need C extensions, but it sounds like I probably overestimated how common they were.
You're spot on with 3 - I don't know how I missed that, but the pattern in the strings should be C Bb Ab G B (natural), like in 211 in the bassoon and 'cello.
Thanks for the feedback and pointers, and for taking the time to listen!