Architect needed for us to submit extension plans to council

Hi there, we're looking at a very simple flat roof extension, extending out from the original flat roof, so we can submit the plans to Dacorum council & get planning permission for the Spring. (you must have experience in this.)

We're simply looking at extending out 2.5 meters and carrying out the simplest extension possible that conforms to building regs.

The new extension size dimensions are approx: wide: 5.0 M X 2.5M out (deep) external dims.
The current flat roof extension is wide 5.0 M X 2M (deep) external dims.

1. The old coal shed (right) will need to be taken down.
2. Looking at demolishing the rear wall, so it's seamless inside if possible. We will need an engineer most likely.
3. We want to add lanterns to the roof, in the old flat roof & new flat roof.