I imagine John you’d pleasantly* surprised by your survival chances.
Even if they’re running sbirs (or more mundane early warning and tracking) from up there it would likely be a “conventional” (non launched low yield – easier to get a bin lorry up there than a cruise missile, let alone a multi stage rocket- to disable rather than needing to destroy) preemptive strike to minimise defensive capability and tracking of icbms which would then launch on primaries. nukes would be hitting command and control, launch sites and infrastructure which are useful in the aftermath (major train lines/junctions/depots, airfields, motorways etc). In a post nuclear world a listening and tracking station hasn’t much to do, it’s usefulness being largely outlived (and arguably mission failed)
(though of course anyone launching at the UK has a big enough arsenal and range to be fairly free in their target designation without too much concern over value, or has smuggled one in so would go for a major pop. centre for maximum retweets)