As an Englishman, I have a lot of sympathy for Roz's point of view. Without wanting to argue the rights and wrongs of particular historical events, I think she is right to say that the English treated Ireland shamefully for nine hundred years and I can understand her bitterness. The Welsh too have suffered from English imperialism and racism - the suppression of their language in the education system in the nineteenth century was criminal - but nothing like as badly. As regards the Scots, I don't think things are quite so clear cut.
I believe that the Irish (north and south), the Welsh and the Scots should be allowed complete self-determination. If they want to be independent countries, fine; in that case, perhaps we the English should pay them appropriate reparations to reflect the extent to which we have exploited them over the centuries.
But I think the English too should be allowed self-determination. England was an independent unitary state for nearly as long as Scotland and a lot longer than Wales. (Ireland is more complicated, I think). I believe that we are a nation, and should be allowed to govern ourselves.
But I hope we shall always have very close and friendly relationship with our neighbours in these islands, with whom we share so much history and culture, and continue to welcome settlers like Roz who have so much to offer. Indeed, I think our frontiers should be as open as possible to all comers. I really resent the way 'English' has come to be used in a racial sense. In my view there is an English nation, but I do not believe there is an English race.