Ian,
In third world countries like England, they may not have these protections for the public water supply.
Here in the US, they have plumbing codes for outdoor faucets that will be used with hoses.
That's why we can drink our water from the tap, we don't need "bottled" water. Pretty sweet huh?
This is a washerless frostfree hosebib that I like to use. It's a 1/4 turn faucet, turns smoothly, protects the public water supply, and it's frostfree.
I don't have a problem with the price that the other plumber charged.
My sister was quoted $450 each to replace hosebibs in Tacoma Washington from a plumbing outfit down there.
With any faucet replacement, there will be travel time, and shuting down and turning the water back on.
That will take some time right there.
My only knock on the job listed at the top of the thread, was the type of hosebib installed.
It is a high flow valve, granted, but it should have been legal too.
She can still thread a anti-siphon to it though.