Merlin need to stress the economic benefits to the local council better and in exchange they will get planning permission. It is pretty much the same process for any large project. If you are able to make it appealing to the locals then it is fine. That could consist of bringing in more tourists for local B&B's/Hotels or resurfacing a road for them. For merlin the park to invest in is obviously Thorpe. Its the park they can do the most with. Close to 2 motorway junctions, relaxed planning permission, close proximity to London and Heathrow. If they can solve the space issue then it would be a no brainer.