There is nothing to stop a party that may be affected, but not listed in the consultation list WRITING to everyone in the consultation list expressing their concerns and the reasons behind the concerns. It may make the person on the list aware of detail that they may have missed and influence their response (or indeed prompt them to make a response) by the deadline.
It might even be worth anyone with objections trying to co-ordinate a signed petition endorsing common objections to the proposal. A copy sent to the CAA and the persons listed on the consultation list would at least bring focus on what GA pilots using the area think. This could be co-ordinated by email.