Planning application - they are developing on our land

Freecall

If you need to buy time then look at the Certificate of Ownership which the applicant will have submitted with the application.

Either it will say that they own all the land involved in the development (which from what you have said they do not) or it will say that they have served notice on the owners or the land (which again, from what you have said they did not).

Then write to your Local Planning Authority (the planning office) and make it clear that the Certificate of Ownership has been completed inaccurately.

They will want evidence that you own the land but ultimately it will invalidate the application and force re-submission.

It will not prevent the application being re-submitted but will buy you time.