I have been asked to research guidance for the Heathrow Local Impact Report.

Statutory guidance on Local Impact Reports (LIR) is comprised within paras 52 to 57 of Planning Act 2008: Guidance for the examination of applications for development consent: attachment 1
The Planning Inspectorate has also produced an advice note (Advice Note One) about the production of LIRs: attachment 2
All LIRs submitted to historic and live examinations are available to view on the discrete project pages on the National Infrastructure Planning website. Three in particular have been identified by the Inspectorate as good examples, hosted here: attachment 3