Jacko
Draw a circle of say 1200nm range from Moscow or Beijing and see how much sea room there is. Alternatively - note how many airbases are within that distance. You won't get a TLAM class cruise carried internally in anything stealthy, so you're either in SRAM territory plus unrefuelled combat radius of some form of Stealth aircraft (F35 anyone), or you're doing a large unstealthy cruise missile carrier - yet to be developed of course - from UK.
Either way, without a stealth cruise missile - again yet to be developed - there is a significant vulnerability to AAW defences of the weapon on the way in. The time element @500-600kts still militates against deterring any regime concerned only for its own survival.
"Cold war thinking" is not necessarily outdated when nuclear deterrence is the subject.......it's only "progressive" think tanks that try to label it that way.