From the HS2 Consultation documents:
The questions on which the Government is seeking views are set out below. In each case, the Government is interested in whether or not you agree with its proposals and why, as well as any additional evidence that you feel it should consider in reaching its final decisions.
vi) This question is about the Appraisal of Sustainability (Chapter 5):
Do you wish to comment on the Appraisal of Sustainability of the Government’s proposed route between London and the West Midlands that has been published to inform this consultation?
Chapter 5 has short summary about the Appraisal of Sustainability: the actual documents are hundreds of pages long.
However, in spite of those hundreds of pages, the Environmental Impact Assessment has not been published yet.
To give an informed answer to the consultation, you need these detail and the EIA.
However, it may be worth looking at the local plans which are available and comparing them to the actual landscape. Every time a new plan set of plans have been produced, new problems are being created due to the lack of knowledge of the localities by the people who developed those plans. The Department for Transprt needs to be told about these problems.