If there are not currently any leaks them personally I wouldn't bother. Surveys never ever come back with a clean bill of health.
If he/she removes all the moss (who gives a fuck about that, it'll grow back anyway) and fixes the small pointing jobs, then I'd expect 1/2 - 1 day's work, so £200 - £300.
If you want evidence of the issues (and latterly the repair) then ask for photographs to be taken.
If there are not currently any leaks them personally I wouldn't bother. Surveys never ever come back with a clean bill of health.
If he/she removes all the moss (who gives a fuck about that, it'll grow back anyway) and fixes the small pointing jobs, then I'd expect 1/2 - 1 day's work, so £200 - £300.
If you want evidence of the issues (and latterly the repair) then ask for photographs to be taken.