A tree beside a house does not establish that a gutter is blocked. Tell us what you have actually seen: leaves above the edge, water spilling at one point or an outlet that appears obstructed. Include the affected side of the building in a ground-level photograph. Avoid guessing which neighbouring tree caused the problem.
For a Chislehurst enquiry, give the postcode and explain how the relevant garden or passage is reached. Say when the gutter was last cleared if known, and whether the present problem developed afterwards. These details help describe the job without inventing a clearance schedule.