I'm just going to reply to myself then :')
So for past year papers the most complete collection I've found (for history) is on papacambridge.com, with a couple of missing papers from other sites. I still have a few gaps though.
One thing I want to point out is that examiner reports are the best resource a self-studying student could have. You have questions, the mark scheme, and then an entire document telling you what the examiner wants or dislikes in answers, as well as common mistakes. It's basically the next best thing to a teacher. Use them.
I'm still looking for the scheme of work so please let me know if you can access it!