No problem, but the electricity has to get there somehow. I dismantled the existing doorbell and pulled the electricity through the pipe of the normal doorbell. This will probably be difficult in a rented flat, depending on the standard of the fittings.

Yes, I have mounted them on screwed Feller 2 blind covers. The top-hat rail transformer supplied must be used. However, the Unifi WLAN chime (not included with the G4) is far too quiet and I had to retrofit a Honeywell radio chime (the control relay is included with the G4). The system works well, except for the occasional phantom ringing when Unifi restarts the G4 after an update or after a power cut. This can be very annoying, but rarely happens. Fortunately, you can mute the Honeywell chime at night.