[Hanuman]

If this were me, now. I would

1. Fit the new battery.
2. Monitor how things are going. How frequently did problems occur before? Or what was the approximate time between problems? Days, weeks?
3. Reinstate items like alarm bits, once confidence has been restored somewhat.
4. Monitor how things are going.

It's the wrapped up ends, stuff dumped in the boot, jobs not done as discussed crap that has me doing as much work myself, as is possible. Even some of the more respected people have let me down so badly in the past, and when you don't know what has been done by others, it just adds to potential issues.

Good luck