So the fix was to remove the lock file after a reboot... Very tedious.
I found the easiest way to remove the lock file on start up was to use cron.
cron has a special built in string which allows you to run something once at start up (from 'man 5 cron'):
Instead of the first five fields, one of eight special strings may
@reboot Run once, at startup.
You can test this out by running a test which creates a test file (add this to /etc/crontab):
@reboot cricket touch /tmp/testfile