Unless the car is parked directly by their single-paned open window and they are light sleepers, then believe me, there's no way that beep will disturb anyone.
Sounds always sound louder to you when you are out at night, but in reality it's more to do with your heightened senses than anything.
Thanks for the responses which helped me establish some perspective as no-one has complained. I'm still in my first year of urban on-street parking after 30 years of leaving the diesel warming up on my own drive so I guess it's an improvement all round! I still can't get over the ability to defrost the car from the breakfast table.
@Clivem21 My neighbour was a bit like 'what is so good about a Tesla anyway'. He understood one benefit when it was -10 and my car was toasty and defrosted while has was freezing scraping his car! No more 'funny' comments since that day