GB wrote in :

I've just fitted a new tap to our kitchen sink. It took me nearly 4
hours. That did include altering the pipework. Plus puzzling over the
instructions on the rather complicated Bristan Easyfit tap. Great
taps, awful instructions.

But 4 hours! I'd expect to pay a plumber no more than £100-150, and
that might well include coming to quote first.

You probably read the instructions - a tradesman won't as they consider
they know everything - then end up with parts left over - or wrong sealants
or things used.