Start by describing what you see
Moss on a path or collected at a gutter outlet may have come from a roof above. Leaves and other debris can collect alongside it. From ground level, note whether the problem is concentrated in one corner or appears along several elevations.
You do not need to identify the exact cause yourself. A clear description and wide photographs are more useful than climbing up to inspect a gutter.
Separate the source from the obstruction
Clearing material from a gutter addresses what is in the rainwater channel now. If material is continuing to come from a mossy roof, it is worth discussing the roof as well. These are connected tasks, but neither automatically includes the other.
David offers both roof cleaning and gutter cleaning. Ask whether the final gutter clear should follow roof work, and confirm the sequence in the agreed scope.
Overflow does not always mean a blockage
Water escaping at a joint can also point to a defect. A sagging run, damaged seal or misaligned section may require repair. Cleaning is not a guarantee that every rainwater problem will disappear.
When you contact David, describe where the water goes and whether it happens only during heavy rain. A safe video taken from the ground can help show the location, but do not stand beneath a working area or attempt a risky inspection.
What a quote should clarify
Check whether internal debris clearance, exterior gutter washing and downpipe checks are separate. Ask which elevations can be accessed and how any section above a conservatory will be handled.
If roof cleaning is also planned, discuss protection below the eaves and how debris will be collected. The aim is a coherent plan for the property, not several disconnected tasks.
What you can monitor afterwards
Observe the roofline from the ground during later rain and report any persistent overflow at a specific point. Keep records of what was cleaned and any defects identified so a repair contractor can distinguish the remaining issue from ordinary build-up.
For a quote, contact David with your postcode, property height and photographs of the roofline and access.