Due to H&S etc you need 2 men and a scaffold (from £200 for 1 side of house) really. labour will probably be about £400. You could half that cost if its just one side of the house, 6-8M.
Its not worth going for the cheapest quote but the company that will do the best job in the safest manor. They should also have proper briefing, training, planning and carry out a risk assessment.
If you roof felt is rotten along the edge then water will be penetrating your timber fascias.
If someone offers to do it off a ladder, dont go for it as you maybe held responsible if theres an accident.
Mark www.highvac.co.uk
November 2008