You may want leaves removed, an overflowing outlet checked or an explanation of a drip. Name those aims separately. Wider photographs from safe ground positions can show the gutter, pipe and surrounding building. They support the enquiry without being a complete survey of the roof or concealed drainage.
Give the Kensington postcode and known earlier work. Explain any section you cannot see and who can arrange entry. You do not need to decide the fault before asking which inspection and cleaning tasks are appropriate.