What an interesting question.
There are some lovely jobs in Evesham town centre just crying out to be done. People in the street comment on the gutter gardens.
In every case, the gutters look like they will come away from the wall if a sparrow farts in close proximity.
I wouldn't touch them with a bargepole. Quite apart from the possible claims from the landlords, imagine a section falling onto a mum and babe-in-arms.
I stick to domestics and only on newish houses or very well-maintained older ones.
Commercial contractors, I imagine, must have experience of less well-maintained and have probably got the details of a building contractor close at hand all the time.