Having found an old database backup, I’ve seemingly been able to import content into a second wordpress install (to avoid breaking this one!).
I just need to fix a few things and then I can export the missing content hopefully (mainly just needs images uploading to prevent broken images/links).
Cross posting should also be working now hopefully, so this should appear on my DreamWidth account (instead of LiveJournal, of which I’ve deleted all accounts and content due to new TOS), as well as the wordpress.com blog. It does at least allow a second level of backup for the content at least.