I had a bathroom fitted by a large DIY chain. 17 mths after the installation started, it's finally finished.
It has taken this long because problems kept occuring, the fitting was substandard, holes were left in external walls (not filled as they should have been) causing water ingress and damaging cavity wall insulation - I had another builder fill these when I discovered the problem. I had to get an emergency plumber out to fix a toilet that hadn't been fitted properly plus several other issues including faulty cabinets and leaking bath which damaged newly plastered kitchen ceiling.
The bathroom cost £4600 of that installation was £2700. I think that 17 months to get it done properly is ridiculous. Am I being unreasonable, now that all the problems have been corrected, to ask for 50% of the installation fee back.
I am fairly sure that their service standard isn't that a bathroom will be fitted within 17 mths therefore I think they havn't delivered the service I paid for.