hehe, nice. I think you're missing a few of the implications of a divided England - small if extant empire; unlikely to have a socially important civil war; therefore no platform or receptors from which to make social and political emancipation an increasingly-global phenomenon, therefore no no Presidential system or socialist attitudes in the 20th century etc, but I like it all the same.
I agree, with much of your post - however while the english civil war would not have happened, that doesn't mean we couldn't have something similar happen, and certainly democratic, emancipatory, and even socialistic ideas, and desires have a habit of appearing in all sorts of societies, at different times for all different sorts of reasons.
I have obviously glossed over a hell of a lot of events...
Acts of union - You're absolutely right, but these acts of union I see as having been basically signed between local overlords/parliaments with tiny electorates, who had been appointed by the dominant nation anyway, and where probably even just local offshoots of the relevent royal family already, a defacto union would have existed for years beforehand between the aristocracies of the nations involved.
In the wider world I think Albion and Jorvik would have established smaller, more scattered overseas empires like the OTL Dutch, and Belgians. TTL would have seen a bigger Spanish Empire being superceded by the French Empire as the worlds largest, and french probably taking the place of english as primary language, thanks to the substantial french influence on North America...
In Ireland I see a messy situation with scottish and jorvise protestant settlers dominant in the north and eastern counties, with much resentment from the catholic irish minority, and in the south anglisc catholic settlers taking great swathes of land in sparser numbers, but serving as slightly more sympathetic landlords. Ireland by the 20th C would probably be divided into two seperate independent states, but with the north eastern one basically being a client of Jorvik.
In terms of technology and wealth I think that Jorvik could have become a real financial and industrial power house, with the money raised from wool, mining, oil, textiles etc actually not being sucked into London, while Albion would have a poorer than OTL rural farming based ecnomy in the west, bolstered by the south Wales mining industry and successfully turning London into a financial centre, by remaining outside the great continental struggles between France and the United Kingdoms (Germany-Austria-Switzerland), and indeed with french being widely spoken in London, thanks to many catholic refugees arriving in the 18th century from France and Belgium. Broadly speaking I think TTL Brtiain would end up margnially poorer than OTL without a massive empire to loot, but not that much.
ETA: I might actually draw up a timeline for this...