Habitable room and the 45 degree rule

John, Assuming the planning pack has been validated it will be available on the planning portal. I would discuss your plans with your neighbour, while it isn’t essential they agree with what you are proposing it will make it easier for you when you superseded the drawing and if it is raised by the officer you can explain The reason for the change and hopefully confirm neighbour support. I have also found that planning officers are more responsive and are acting with more autonomy currently as they have been working from home. No harm in dropping them an email.

You do not need to resubmit a new application, you can amend the over depth of the extension and resubmit to the planning officer allocated, and provide reasons for the amendment. They will supersede the previous drawings. The only concern would be if the consultation period has ended if so the revised plans would need to be sent to the neighbouring properties again for consolation which will extend your application up to 4 weeks or by how long it has been out for consultation.