Concur with ELondonPax, although I don't live in London, having stayed with friends on a regular basis, who live near various heliports, the noise pollution is unbelievably intrusive.
Unless you've experienced 3 or 4 days of it, you probably wouldn't appreciate that its far worse than the approaches and departures to and from City Airport, or to a lesser extent, Heathrow.
I'm usually the first to baulk against NIMBYs and I also fully appreciate the business need for the flexibility of helicopter travel to and from the Capital, but in this instance I would be fully against any expansion of current facilities or the implimentation of new heliports.