"And it will cost the same as Galileo, but we don't get to split the bill with 27 other countries."
It'd probably cost more, because I wouldn't trust the UK government to run any project competently.
But the development work on the clocks has already been done in Blighty. That was hugely expensive and the one genuinely new bit of development needed. The rest of it's fairly ordinary space-going radio gear on what might as well be a standard satellite bus plus the usual space-hardened computer to run the fancy stuff - but they get more capable and/or cheaper with every passing year.
So it *ought* to cost less, what with all that and cheaper launches now being available thanks to SpaceX et al., at least when compared to the first Galileo launches.
It wouldn't, though, would it? :-/