I normally hate those sort of sights but I think this one is more realistic than most. It does mention unforeseen bits and bobs and I disagree with some of the pricing.
I had to quote for a bathroom the other day, supply and fit etc. Job included ripping off all the old tiles which were floor to ceiling and rip up floor tiles, re-new bathroom suite, new thermostatic shower replace existing rad fit new one and trv, ihibitor etc.
Having flicked through the prices she's got a bargain. I think I'm still expensive though, some cowboy will do it for less with no insurance etc. Thats life though.