"The Republic has never recovered by the massive loss of population by death and forced emigrations of the mid nineteenth century,"
Strange you trot the above out every opportunity yet never mention the highland clearances. Were they just a walk in the park?

" thanks to Britain developing industry in the North East, giving the best land to settlers than hanging on to that bit after independence"
Rubbish. The protestant majority wanted to remain part of the UK.
Should we root out the angles and saxons and vikings on the basis od their DNA and ship them out after x hundred years. This makes as much sense as you using the term "settlers" just to make a pathetic divisive argument. The development of industry in the north not the south was primarily due to geography Take away shipbuilding and linen and there ain't a lot left, and both have been in serious decline for decades.