You can complain to Heathrow.

noise@heathrow

I’ve sent them an email but very much doubt anything will be done about it.

The noise is the in bound planes on long haul. Heathrow’s bold claim is “we voluntarily don’t schedule any flight (outbound) between 12 - 6am”

Scale of the issue can be tracked here when ever your next up at 4:15 and wondering why.

https://www.flightradar24.com

Have now way of really proving there’s been an increase but it’s been about of being frequently disturbed in the early hours.