How Many Hours to do This

I am not looking for a price guide estimate or material cost, I merely want to gauge how many hours it would take a competent builder to complete the following to some outbuildings I have. The house is Victorian.

1. Demolish shed. The base is 8ft by 6ft and 6ft high. The roof is 3 corrugated sheets. The 6ft wall has door and frame. The 8ft wall has 40% window area. It only has 3 walls as it is built against party garden wall. The construction is blocks at lower level and bricks at higher level. The other end wall partly comes down( see below).
In the shed is a redundant stack/vent metal pipe which is redundant. This needs capping at ground level.

2. Form Base. The inside of the shed is concrete base but is 50mm below outside paved area. So the 8ft by 6ft footprint needs 50mm concrete.

3. Outside loo. Remove door and frame and fit new door and frame.

4. This is complicated to explain!! I have an outhouse that is between the outside loo and the shed for demolition. The shed is on a higher level, by some 3 feet, to the outhouse. The outhouse stays and shares a party wall with the shed to be demolished. That is why part of the shed wall stays.

Okay work to be done on outhouse is to remove corrugated roof which is 3 sheets, total area approx. 6 ft by 6ft. Take away front of outhouse which is wooden.
Put TwinWall roofing on 6ft by 6ft, which will be abutted to outside loo wall and partial shed wall and garden wall.Reconstruct front of outhouse which is 5 ft high and 6 ft wide, with door and frame, and a t&g wall for the rest of the width.
Put on gutter board and gutter.

I am aware that the corrugated sheeting might be the old asbestos based type, however, it is not broken.

As stated I am only asking how long each of these 4 tasks would take by a competent tradesperson, I am not looking for costs or material costs.

I would really value opinions.