That's a pain, 8. I removed mine months ago (I now own the home and can do what I like). I should be putting fresh batteries in an putting it back up - but, as with all alarms, you get so many false alarms it's annoying.
My dad had a burglar door alarm on this place for years in the 90s but he had to get rid of it because possums kept setting it off - several times a day.
As far as the old house goes - the fixups go on. The mould problem was sorted out by having the cornices replaced. I'm getting the ceiling cleaned out next week. Quote = $800 - major job with lots of hazmat procedures due to possible asbestos and lead paint.
I've had respiratory problems since moving into this place and it seems there are heaps of rat droppings up there, which I'm told is common in areas with a lot of vegetation. Apparently rat droppings can he hazardous
in a number of ways.
After the cleanout there's rat proofing. Then put in insulation. Then replace all the electrics (old and dodgy), then add solar panels, then replace the windows (paper thin and the old wooden frames are rotting) and blinds, then repainting, then recarpeting, then ...
It's the result of 50 years of bare minimum maintenance ... Dad preferred not to spend money in the same way as most of us prefer not to be thrown into a pit of boiling lava.