Once a development has been approved it must be carried out in accordance with the approved plans and any conditions attached to the permission.
Further details for approval
Your planning permission may include conditions that require you to submit further details for approval within an agreed timescale (often before development commences). It may be necessary to re-consult on these further details.
The case officer will normally be able to advise as to whether any changes need to be formally approved.
It is recommended that you get written confirmation of any amendments.
Amendments to the approved plans
If further plans are required it should be made clear on plans what changes are being made to the original permission.
If the changes are deemed to be different from the original proposal it may be necessary to submit a new application.
The responsibility lies with the applicant or the developer to notify the Council if amendments to the approved plans are necessary.
Even if planning permission has been granted you may also have to comply with other requirements like the building regulations.
You may need to get landlord approval if the property is leasehold, and there may also be restrictive covenants, which affect your property.
If you are unsure what you are required to do you should take legal advice before starting work.