Post-apocalyptic Future UK Flood Map

In the process of preparing the backstory for one of my works (I won't say which), I've produced what could be a post-apocalyptic future UK map. Combining a city map with a relief map (with some tweaking) has resulted in the following:

From the upper right scale you can see this essentially highlights the separation between lowlands--grey--and highlands--green to red. One this to note is that the 'lowlands' on this map are still up to 50m above sea level. I intend to use this as a map of future flooded UK, where the lowlands are submerged. Obviously, in addition to polar ice cap melting, this would require some seismic event.

Regardless, the results are interesting, suggesting that England is most vulnerable of the three UK countries and would be most changed by such a series of events, while Scotland and Wales would be almost unaffected. In fact, England would be reduced to a peninsula off Scotland, an island in the southwest, and a small archipelego. The seat of power would possible shift to Birmingham, as London would be underwater and Southerners have very little respect for Northerners, in general.

This new geography is ripe for stories, suggesting many questions about a shift in the balance of power. For example: Could England remain in control or would Wales, and especially Scotland, reassert their power vying for independence or sovereignty over the new British Isles? How would the surviving cities, most now becoming coastal, adapt? What type of society would arise now that the seat of power (government and monarchy) has been destroyed.

So much food for thought :))