[hgomersall]

We went through a similarly priced renovation. We had a different objective to many doing similar to us, which was to improve the energy efficiency of the house. It was interesting to see how incompetent the tradespeople were when the requirements deviated slightly from the norm. We had the usual shenanigans of course: the electricians gave us a bill that included a huge amount for materials, so we asked for a breakdown and found that they'd charged for hundreds of meters of cable that I could prove were not installed (impedance measurements gave me a good upper bound on the total installed length). I simply refused to pay more than a nominal amount until I was given an accurate bill with evidence, which never came (I suspect it wasn't malicious, it was just each electrician buying a reel of cable and chucking the remainder in their van for future use).

I also got into quite a heated argument with a plumber about static vs dynamic pressure and flow rates (it turns out fluid dynamics is not really part of a plumber's training).