As a domestic customer with a one off job you are subject to the whims of supply and demand as far as price and availability to do the work are concerned. What I think is important in your circumstances is is to agree with the plumber the standard of workmanship, tolerances and finish that you are paying for. E.g., it's a lot quicker and easier to install plastic pipe and flexible tap connectors than nicely done copper with rigid connections. Make sure the system you envisage is what the plumber is planning to deliver.Well TBH I always go with the person I get that good gut feeling with, regardless of their quote amount. I'm always willing to pay for quality work. The plumber of the lower quote does work with the electrician I've booked but I guess the base question is, considering the work of the 1st/2nd fix, does £2300 represent a fair price for parts and labour? That's why I'm asking the pros on here as I don't know if even that is too steep?