Bungalow Rear Extension Design

I'm seeking a skilled builder to create a rear extension on my bungalow. The primary purpose is to add additional living space, specifically a bedroom and a living room.

The bungalow is 8m square, and looking at a rear extension of 4m x full width. On the attached very quick plan we have in mind, the original bungalow area is outlined in red, so we're talking about moving the rear left wall into the existing area to make an en-suite for the extension main bedroom, and losing the rear right wall (existing kitchen) to open up to a kitchen/diner/sunroom.

These are only my ideas, and they seem to work for what we want, but open to any design suggestions also, but this is retty much what we'll need for living.

** WE OWN, BUT AREN'T CURRENTLY LIVING HERE YET, WE PLAN TO BE IN BY THE END OF THE YEAR IF ALL GOES WELL** So no immediate hurry, I'm just trying to get as much info and help as possible up front.

Design Requirements:
- Modern, traditional, or minimalist aesthetics
- Oak/mixed timber frame design preferred, but also happy with traditional build

Ideal Skills and Experience:
- Expertise in timber frame construction
- Experience with modern/traditional/minimalist designs
- Knowledge of local building regulations and permits
- Strong project management and communication skills

Please include examples of previous work and relevant qualifications in your bids. I hope that's enough info to be getting on with.