Sounds like you have a lot doing with possible multiple tradesmen: electrician, plumber, fitter, chippie, whoever. And I'm unsure how many days work that would be. Labour can add up.
On the one hand £6.3k to revamp the whole of say ⅛th of your, what, £180k house?, seems not unreasonable; when you price it bit by bit it may not seem so justifiable.
I think you would do well to follow MM's advice, try to work out what is going to be spent on materials etc, and see whether what is left is reasonable in terms of how many are working on it for x days.