Any future alterations or extensions to the development or other statutory applications will almost certainly require the rectification of planning status of the existing development.
The rectification of an unauthorised development can be done in two ways: the first is the correction of the relevant non compliance or the receipt of a subsequent permission for the retention of the unauthorised structure.
The latter option of a retention application comes with no comfort of success and, even if it is successful, it can be expensive and can result in further onerous conditions.