Hi Nigel.
First off, don’t assume that you will not achieve your applications for planning permission.
We had similar naysayers at our Club whose crystal balls were off kilter as was proved 2 years later when we gained change of use!
Your committee will find Andy Symons at the BMFA (Club Liaison Officer) most helpful with all the right information to hand.
As far as planning consultants go, we found that the going rates for these guys can be eye wateringly heavy.
We negotiated a deal whereby the consultant supplied the ammo and the committee did the working of the AK7 so to speak. This more than halved the cost of a consultant.
Depending on what your guys feel that they can cope with, the consultant can take over the other bits.
There are quite a number of references on the web where guys have put up pages describing their experiences with the authorities and gaining some if not all of their requirements for a flying site.
Even “green belt” land is not sacrosanct, it is not unknown for flying clubs to occupy a prime agricultural field without too many onerous conditions.
Regards.
Paul.