It's not ideal, I moved away from the river front because of this and the boat noise at night. Helicopters navigate thru London along the Thames at night so it's always going to be there, also the area seems to attract jumpers so the Met Police helicopter's are very busy, follow them on Twitter for info on their movements.
I don't think this is just the usual helicopter noise. Since a few weeks there's been a real surge in day and evening helicopter flights over the area. Not sure why---I thought it'd have to do with the Queen's 90th birthday, but that wouldn't explain why they're still going. Bloody annoying.
On Saturday 25th June 2016 and Sunday 26th June 2016 between 0800 and 0930 low level helicopter filming operations will take place 200 feet upstream of Tower Bridge. The filming will involve crossing the Thames from north to south at a height of 100 feet above the river.