There was an interesting article in Pilot about this recently. Basically (according to the article) everything is governed by the County Planning Orders (or sommat like that).
If you get 20 local residents writing (in deference to the local airfield) to the local planning dept just before the next 5 year proposal is due, then these 20 letters will count for a lot. It's a question of when the next planning orders are due to be published, and how many people oppose/ like an idea.
Not explained very well, best refer to Pilot Mag this month for the full details. Nigel Everett's page.