What is a Local Plan?  It is a framework for future development in a planning authority area. It contains policy that guides the decisions that are made on planning applications. It must address the needs (supported by evidence) and opportunities for the development of housing, the local economy and infrastructure. It must safeguard the environment and heritage, enable adaptation to climate change and help to ensure good quality and accessible design. The consultation stages of a Local Plan are as follows:

Initial stage of consultation (Regulation 18): There is flexibility around how planning authorities carry out this stage of the Local Plan preparation, as long as they comply with specific requirements in Regulation 18 of the Town and Country Planning Regulations. They must consult ‘specific consultation bodies’ and, more general bodies, residents and businesses that the authority considers appropriate, of proposals to develop the Local Plan. It must invite comments or representations around what the plan should contain and take them into account.
The Old Oak and Park Royal Development Corporation (OPDC) consulted on this version of its Local Plan and the evidence based documents that it produced to support the draft plan (which can be found here) from the 4th February until 31st March 2016. The corporation held consultation events through which members of the public were able to influence the following (regulation 19) draft Local Plan. The GUA encouraged its members to attend these consultation events and held some of its own.
The consultation generated 2,639 individual responses by email and letter, 1,200 comments at workshops and drop-in sessions, 28,000 web views from 6,000 visitors, with 200 comments and 80 tweets. The GUA submitted a substantial collaborative response to the draft (regulation 18) Local Plan, and a response to the evidence base documents which a number of its members also submitted in full or in part. GUA support staff carried out an analysis and a summary analysis of the responses to the Local Plan consultation which notes where changes would be made by the OPDC.
Final stage of consultation (Regulation 19): At this stage, planning authorities are required publicise the version of their Local Plan that they intend to submit to the Planning Inspectorate for examination, to enable comments or ‘representations’ to come forward from members of the public to be considered at an examination. The formal consultation period for this version of its Local Plan was held from 29.06.17-11.09.17. It organised some open consultation events.
A draft regulation 19 draft Local Plan version must have regard to national and London-wide planning policy. The OPDC was required to carry out an appraisal of the sustainability of the proposals in its draft Local Plan and prepare a report on the findings of the appraisal. A Local Plan must meet 'tests of soundness'. 
These tests are that the Local Plan must be:
  1. Positively prepared - based on an objective assessment of development and infrastructure requirements in the OPDC area and be consistent with achieving sustainable development;
  2. Justified - founded on robust and credible evidence including evidence of participation of the local community and others having a stake in the area; research or fact finding showing that the plan is justified by evidence that is up to date and convincing; the most appropriate strategy when considered against reasonable alternatives
  3. Effective - it must be deliverable, flexible, able to be monitored and be based on joint working with neighbouring authorities.
  4. Consistent - with National Planning Policy Framework and be in general conformity with the London Plan. Where it is not, it must give clear and convincing reasons to justify this.
Responding to regulation 19 Local Plan consultations is a bit more technical than the earlier stage of consultation as comments need to focus on the 'tests of soundness' which the planning inspector will consider at an Examination in Public. 
See also GUA's work on the OPDC's Local Plan
It was reported at the November 2017 OPDC board meeting that the OPDC planners would be working on for the next four to five months on the Local Plan [and really should engage with those who responded to the consultation] before submitting to the Planning Inspectorate for an Examination in Public. It seems that this is unlikely to take place until autumn 2018.
The OPDC published on 14th June 2018 a second revised draft Local Plan.  The deadline for responding to the consultation is 30th July 2018.

Click on links (in orange text) to relevant documents or pages