Guidelines V law. very different .But here is another side to think about .Ask them to show you the cameras display as they might be shallow angle types rather than super wide etc /So might not worry you that much. The other benefit is one day you might want their recordings if anything happens !
Fully agree with this. My cameras cover part of my neighbours drive. Just enough to see if anyone breaks into their car.
And yes, the viewing angle of cameras can vary hugely.
Get them to show you the live feed so you can see exactly what is covered.