Residential wrap around rear and side extension

I seek an architectural designer to produce detailed plans for a wrap around rear and side house extension plus a new front porch. Once the design is agreed I would like technical drawings and specifications to pass onto contractors for pricing. Finally, I would like general arrangement drawings visualising optimised room layouts and functionality within the expanded space. The designer would work from existing pdf planning documents and liaise directly with me to refine the design proposal. I would like a fixed price quotation for the works