Niall,
I am not saying that the developer does not influence the EIA through the nature of the project but what I am saying is that the nature of the EIA is as a direct result of the proposed development. It would be incorrect to suggest that the applicant picks and choses what the EIA covers regardless of the proposal.
My experience is that the applicant has an initial discussion with the planning officer about a basic proposal and will through this get an idea of what is, and is not likely to pass. The applicant will then get a basic outline of the project including various studies which might include environmental issues, archaeological, traffic, required building, and so on. To do this the applicant might use consultants or not. With this outline proposal the applicant will meet with SNH, SEPA, County Forester, County Archaeologist to get comments and concerns about the proposal.
It is at this point that the applicant will have to decide on either full or outline planning and assuming it is full planning will employ an approved Environmental Consultant/s to carry out the various required assessments. The scope of these assessments are set by the planning officer based on the input of the various bodies who's input is based on the outline proposal the applicant presented to them.
It is SNH for instance that might decide that a bat, red squirrel and badger survey is needed but might decide that no assessment of Owls is needed. It is not the applicant. The applicant only influences the choice of survey and assessment through the proposal and in no other way.
I do not disagree in general with what you are saying other than the idea that the applicant can dictate to the consultant what they have to do which is the kind of what you are insinuating. This is plainly wrong. The applicant can ONLY influence the scope of the proposal. This is in no way a sign of control. Assessments are part of the planning process which is fixed and doe not alter unless the executive gets involved.
Jon