Short term solution:
1. Pink noise generator, through a parabolic reflector aimed at the camera (microphone)
2. Small laser pointer aimed at the camera lens, or if that's a problem legally, a small array of superbright LEDs facing the lens - use some on white, and a few on red, green, and blue.
Call the authorities at the slightest hint of a breach of regulations. Pay for a friend to stay at the guest house and take notes of any code violations - health, building, electrical, etc, then hand that over to the Council inspectors.
In London CCTV cameras, are on the front of shops on lampposts and almost on every street corner.
The black gangs who want to break into a property use non-powerful lasers which they purchase from eBay, not particularly powerful ones. They wait for night-time and they point the laser at the CCTV cameras and it damages the nightvision of the CCTV camera. It creates a scribble effect like a child has used a pencil to scribble on a piece of paper.
It permanently damages the nightvision of the CCTV camera. The camera ends up not switching back to daytime vision it makes the camera useless.
Some of the very expensive cameras have a reset button inside them you have to take them apart power them on and hold down the reset button to reset the camera to factory default settings. Most other cameras in the 80 pounds sterling price range just never work again.