Had this problem a few years back. I can hear high-pitched sounds easily. I can't find my original post, but it was likely a faulty boiler cycling on and off as they do. It stopped not long after I posted! Quick search on here pulled up lots of posts about similar. https://www.eastdulwichforum.co.uk/search/?q=boiler noise&quick=1
I highly recommend Refined Male Grooming in Camberwell, next to Love Walk Cafe. Have been going there for nearly 10 years, not fake, just excellent at what they do.
The few times I have been in there, they are incredibly busy, but once served, they are very helpful. Their pharmacy first service has been great the couple of times I have used it.
also good to keep a journal of times, length of noise. Encourage neighbours to do the same, as that's usually what noise control need to act on things.
Royal Mail will come and collect your parcels from your home if you book/pay it all on their website. You can even print out your own postage for letters/cards. I did all of my Christmas cards that way this year rather than hunting down physical stamps!