I restored a backup of before I updated to the latest release. I am now on OPM5.171019.017. Unfortunately, I have been testing for a week and I can confirm that the battery life is significantly better than the current release.
I'm pretty sure I am. Up till the last update I was hanging around 40-50% at end of day. Now I'm at 22%. I think "system" is consuming more battery than it should. "apps" looks to be fine.
Accidentally switched Network Type to LTE only in Mobile Network settings. Now, that section of the settings has disappeared. Looks like a bug, and I can't call anyone now. Would rather report the bug than reinstall the whole ROM.