You guys would have to be deluded to think that Derron has such power in this. Merlin would not give him £30 million pounds to play with. Derron brown is the creative consultant meaning he comes up with the idea, the back story, ideas for the ride but is in no way given a large amount of input. You have to remember Merlin is a public company and I doubt many share holders would allow them to give £30 million to an illusionist/ mentalist when the idea is to be profitable and to be cost efficient.
Merlin will have a large team of people coming up with the details of the ride and Derron would have come up with the initial idea while then driving this idea to the public as an influential figure