At a very rough guess £1000 + scaffolding (maybe £4-500). But, depends on the length of runs etc. Are you expecting them to do the fascia, soffits and guttering? Do they have easy access? What style of guttering? Solid replacement fascia or cladding? How much remedial work on rafter tails?
Its a tricky one but I've just had a quote of £1250 for everything on a 4 bed detached. I could do it for less but have more important stuff to get on with (and I hate heights as well)