There was no variation across the country, or even between home nations, on who was on the shielding list.
GPs had to identify the qualities flying patents, it was a big task, and (a bit like school return policy) was subject to changing definitions (eg what counted as severe enough in certain conditions where only the most severely affected were included)
I don't think many of the 'vulnerable' list of conditions are likely to be moved to shielded, with the possible exception of type 1 diabetes.
It's currently the 3% of the population who are the most medically vulnerable (substantial risk of death) and as shielding is such a huge ask of people, there's quite an imperative to keep it very much to those who would be most ill, most at risk of severe complications and death
(Do remember that the government did this to avoid them falling ill first and becoming bed-blockers - knowing compliance would be high because of self-interest - not least because of the leak about failing the Three Wise Men test)
Do other countries have a shield list? Or other procedures for the exceptionally vulnerable? If so, who are they for, and what does it mean for the individual?