Quarantine hasn't affected me as our holidays were binned before travel. That said, I don't answer my phone to unsolicited callers, so I wouldn't be answering any calls checking up on whether I was complying with quarantine. Furthermore, I don't answer the door to unsolicited callers. If the police want to set foot on my property, they can attempt to obtain a warrant empowering them to do so. I'm not sure what "knocking on doors" is supposed to prove in any case, given that you're under no obligation to answer the door.