Two Storey Side Extension - Plans, Elevations and Submission

I need someone who can create professional floor plans, roof plans and elevations, existing and proposed, for submission to build a two storey side extension on a detached property. For the floor plans I need professional help with the layout, a combination of style and practicality. If I do these myself (already underway) I do not know the practical ways to keep building costs under control for the proposed plans. The planning authority is Wycombe, Bucks, UK, and I would like the person bidding on this project to have experience submitting the full application so they can undertake this for us.

I propose to build the external elevation of the property on the footprint of the existing boundary (garden) wall. We’ll need to include addition of a side/rear gate in the existing garden wall; new brick wall side elevation of the house - garden gate - old garden wall continues after the gate.

The existing footprint is circa 50msq and the extension footprint is circa 25msq.

This is the planning authority list of requirements; https://www.buckinghamshire.gov.uk/planning-and-building-control/building-or-improving-your-property/how-to-prepare-a-valid-planning-application/plans-and-diagrams-to-submit-with-your-planning-application/