Brick shed

Hello, I am looking for a builder to build me a Brick/breeze/Concrete block shed. How deep should the foundations be? Does a Council inspector have to come and check the depth? I would like the shed to have red bricks along the front and one side which is visible. The back and the other side can be concrete blocks as it won't be visible from my garden. Do I need a double skin for brick walls? Perhaps have breeze blocks behind it for support and to save money. I have tram line at the back and my single skin brick 6ft fence wall has shown cracks at regular intervals. So, I don't want the same to happen to the shed. For the double thickness wall, does there need to be a gap between the walls or can they be tightly adjacent to each other? The shed is primarily going to be used for storage. I am getting the floor and the ceiling insulated. Is it worth getting the walls insulated now, in case I use it in the future as a workroom? Would that increase the cost drastically and reduce the internal size of the shed? I have done a rough plan for my shed as shown below. Not sure of the roof. Should I go for fiberglass or tiled roof? A steep drop is preferable as it would prevent rainwater puddling, but I suspect it won’t be very steep due to the size of the depth. For the inside walls, do I need plasterboards attached to the concrete/breeze blocks and then does it need to be plastered and painted? The windows and the door will be PVC. Do I need a stronger door? Rainwater will flow from the gutter into my flower bed. Will that be Ok or do I need a Soakaway built? I know that would cost more. There is electricity in the old wooden shed, currently situated in the same position. The shed is on a concrete base, although it's much smaller. Any ideas as to how much this would cost for labour and separately how much would the materials cost? How long would it take to build? Thank you.