Interior Design of new build Open Plan Kitchen/family room

Design details: We are currently in the process of building a house, modern home, we are struggling to design the layout for the back of the property, which is why we seek a professional design. I will add the measurements shortly, the property is a 3/4 bed of brick construction with a back extension and roof lantern, the whole back of the property will be kitchen and living area. Please provide approximate cost to design. Thank you Ideas for the visual style: Open Plan modern style Extra notes: