Show the whole structure
Photograph the outside, roof, interior and the point where the conservatory meets the house. Add approximate length, width and height.
Explain what needs to stay
Decide whether you are asking about the frame and roof only, or also the dwarf walls and base. Those are different scopes of work.
Mention services and unfamiliar materials
Flag sockets, heating, plumbing and unknown roof panels. Do not disturb suspected hazardous materials. Ask how any specialist work will be handled.
Check responsibilities
Discuss permissions, building-control questions, access, adjoining structures and making good. Requirements vary with the property and work; do not assume they are all covered in a removal quote.
Agree the end result
Ask what the area will look like at completion, which materials will be removed and what is excluded. That makes different quotes easier to compare.
The work, exclusions and any job-specific requirements will be agreed for your property.