My contention with the setting is that, barring anything in the lore stating otherwise (such as the European Oil Wars), it really doesn't have potential for any sociopolitical and economic commentary comparable to the USA both in- and out-of-universe. Not saying it's impossible; certainly there can be themes of authoritarian control and dependency on a pseudo-fascist aristocra to keep the proles in line, especially when it comes to the dwindling oil reserves, famine, disease, etc.
I think this is kinda what America was going through too (albeit, rationing, but seemed to be less famine (helps with this much farm-able land). Brition went through 2 nuclear wars in the Canon: the "limited exchange" with the middle east, then the Great War. Like a certain real country presently at war that had spent the prior 8 years preparing after a rough war in 2014, they would have been making preparations for another nuclear war as incentivized by their history so: bunkers, arms, remnants old guv, etc. could be plausibly more abundant there than expected in our time line.
Theme wise, while London and most America do have very distinct cultures,we also have the "special relationship" -- there's no reason popular American culture hadn't influenced British popular culture, at least in game, so a British-ized-Americana 50s vibe is viable too.
It has promise, espically because a mod team member impressed Bethesda to hire them (huh, no wonder the mods improve the game -- giant pool of folks that probably know the engine and mod tools, even with reduced functionality in the released version, than many Bethesda folks know and they can edit the source code on the fly...
Then again, several mods for NV were serious disappointments or abandoned projects that weren't finished.
I'll reserve judgment until release.