Many thanks for the useful replies
It is not a specific noise issue, as it is accepted aircraft are getting quieter. But if the new runway goes ahead, the noise footprint will increase the area subject to noise. Heathrow (LHR)cannot explain proposed departure routes on either headings, as routes need to go south and north. Also the current northern runway is restricted to no easterly departures, so not subject to northern & westerly turning departures.
I assume that departures cannot pass across the path of the landing runway in operation, due to "go arounds".
The other issue is that LHR are losing frequency due to the A380 ops being slower on the ground, and wake separation.
I have lived within the area of LHR since early 70's, and no worries with noise.
Thanks again.