Finding an Agent, Architect or Architectural Technologist
There is no requirement to engage an Architect, Chartered Architectural Technologist or a Planning Agent if you are competent to do the work yourself.
However if you do engage one of the above professionals you may achieve a more satisfactory result for the considerable outlay of time and money which you are undertaking.
There are also agents who will complete an application for you, perhaps commissioning a specialist plan drawer for the drawings, but themselves without any professional qualifications, but they may have extensive experience or none, so it is important that you assess some prior work of anyone who you are considering employing.
We are unable to recommend any particular person or practice so please use the links above.