This is an interesting proposal but from the areas of the UK I am familiar with some of this makes little sense. In Greater Manchester, choosing to split Leigh from Wigan is a sensible decision but the way you have partioned Manchester into Trafford and Stockport make no sense. Both Universities in Manchester would end up in Trafford. The road you have picked to be the dividing line is not particularly significant or clear. Meanwhile Wythenshawe is disconnected from Stockport. I get that the borough of Manchester is too big by itself but your map just divides the city at rather arbitrary boundaries and leads Manchester loosing both urban and suburban districts. If you really feel the need to divide it, you would perhaps be better off separating it into an urban core and maybe two suburban boroughs to the South and East rather than trying to haphazardly move them into neighbouring boroughs which already exist.

Meanwhile the North of Ireland is not the worst but it seems a bit odd to get rid of Fermanagh but let every other county still exist (even if it is on the small side). The North of Ireland doesn’t really fit the model very well because you are dealing with a much smaller population density overall but with increasing density the closer you are to Belfast.

It’s an interesting map and I approve of the methodology but clearly in local areas things need to be ironed out by locals for this to be truly great.