Is there a general rule of thumb regarding how much you can haggle?

[Humptynumpty02]

We've had some quotes for a bathroom refit and new heating system with moving our booklet and cylinder from ground floor to loft. I'm supplying all bathroom material suite, tiles etc abd they are providing the heating system, all piping, removing an old asbestos flue, removing a boiler cupboard from the bathroom and building a new stud wall. The company I'm interested in are quoting £10250 & VAT and not really knowing what's fair value, is there any general rule of thumb I can go on to haggle, eg 10% off as a minimum?

Hope that makes sense, we really like this company but their quote is coming up a little over budget and I don't want to offend them whilst also getting a better deal.

We are in Surrey, close to London if that helps. Thanks all.

What exactly are they quoting you for? A bathroom refit including all tiling/plumbing/ electrical/plastering plus boiler installation or all of that plus a full CH system? Are you supplying all of the CH rads etc at is the firm? Is the house empty or are you living there whilst the work is done? Impossible to say without knowing the sq of the house plus the above really. It does sound toppy but if you are creating a bathroom where is there isn't one at the mo plus the associated ag og fitting a boiler plus the required safety rails around it in the loft plus the additional piping to get it up there, maybe not so much!

You're right it was a little vague, they are quoting for:

Rip out existing bathroom
Removing hot water cylinder from bathroom cupboard
Removing redundant cupboard in bathroom
Rebuild stud wall (small)
Refit bathroom with new suite, plus install new shower
All piping associated with bathroom Refit
Tiling
Electrics

Removing old boiler
Install new Worcester Bosch boiler in loft
New flue through roof
Fit magnetic filter to heating system
New pump, valves and pipework
System power flush
Install new megaflow cylinder in loft
Remove old asbestos flue
New programmer and thermostat

I will provide all bathroom suite, shower, tiles etc. They're not plastering and not changing existing radiators.

The house is also empty and it's 2000sq ft.

I'd say conservatively £2.5- 3k overpriced and I'm being generous (and renovate for a living these days). It's likely that they've priced the job with the intention of not really wanting it. Can you get any other quotes?