I've just bought a new kitchen sink and single-lever mixer tap. It's a replacement of an existing one, but slightly bigger. So to install it, you need to remove the old sink / tap, cut a bigger opening into the worktop, put in the new sink, install the tap, seal the edges, done. Plumbing seems straightforward with good access.
I've been told the job will take around 3 hours, maybe 4 if anything goes wrong. Quoted £200.
This sounds high to me - is it? I'm in rural Kent, not London, and the guy who provided the quote is a joiner who does a lot of kitchens and says the plumbing job is easy enough for him to handle.