Issues with latest version - how to downgrade?

Hi guys, I’m running OSMC on a Rpi 2 + external hard drive, eminence skin and no non-kodi add-ons installed (also have sickrage running on the pi).
Sadly, after many weeks of absolutely flawless and snappy performance, the last update broke many things - random and slightly frequent crashes, slight lag while skipping video playback back and forth, and for some reason some settings on my advancedsettings.xml are now being ignored (particularly the option to not show all seasons on tv show menu).
Happy to provide a log, but also would like to know if it’s possible to downgrade, as my latest backup is too old, from when things weren’t so stable - failing that, is there a way to use the version in the current installer without erasing my non-osmc settings on the pi - like the sickrage/transmission setup?
Amazing job anyway, love the platform and would just like to have it back to where it was running perfectly.
Cheers!