Had a 'debate' with the Sainsbury's store management at Witney and some of this cropped up.
If you always warn the customer that there may be loose mortar, cracked tiles, ingress of water, at any point over the structure (that may not be visible from ground level) and when you are up there photograph any problem areas (so it cannot be blamed on you) then you get on with the clean you have done your job.
I personally think it is going the extra mile to offer the minor repairs and tile replacement if requested (you can cost it in, even if it means sourcing) and have an additional bow to your service) or you can just have the number of a professional roofer 'who has helped you sort issues out in the past and is very reasonable' to hand.
Rob
