Hi Matt,
Thanks for your post. The most common reason why you'd see SEP Mobile using more battery than expected is if the VPN is engaged. Do you see a key icon in the notification tray indicating that the VPN is active?
It would probably be best if we could work with you in a support ticket on this, as there are a number of other questions it would be good to answer, and it would also help to grab some logs from the device.
Are you able to raise a ticket with us via the Broadcom Support Portal?
https://support.broadcom.com/web/ecx
Please reply with your case number if you are able to open a ticket, and myself or one of my teammates can take ownership of it and assist you. Thank you.
Kind regards,
Matt McEwan
Broadcom Support