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Most utility layouts are guesswork on their part. Especially when it enters private property.
Any utility up to the meter (gas or electric) is the suppliers responsibility.
Water Companies will try and fob you off that the supply ends at the street stop tap but you should be entitled to one 'free' repair to the main stopcock inside the property. Problem is if a previous owner had one.
We uncovered a yellow plastic pipe on the neighbours side, very shallow in a flowerbed when we were rebuilding party wall foundations.. no boom either but our ground workers come across this regularly, in fact expects it despite what is indicated on utility layouts from highway to house often not that accurate for proximity.