Indeed, however, the problem here is:
1-UK would have to pay for the tomahawk IV to be capable to be launched from A-90 VLS,
2-The sea scalp is not as capable as the tomahawk, shorter range, smaller warhead and is more costly per unit.
3-The UK already will be using the Tomahawk, fired from TT by the UK's SSN's fleet
either way the UK will have to "pay" a dirty word these days, hwever, like you say, we need ship borne crusier missles. Going european is not a bad idea, and of course MBDA will in time develop the capabilities of the scalp missle, but off the bat, your looking at only 3 confirmed coustmers, more in time, like singapore and Saudi navy (all aster users)..