Carp, the attitude "whoever is born after the PoD will be butterfied away" in my hopinion is crippling for you, I suggest to avoid it; If there is not a direct logical reason to butterfly someone off, then that person should exist; It may do different things (maybe not in this case, as independent Corsica's existence can't have changed things in Britain this deeply) but there is no reason to say that person do not exist.
I have to respectfully disagree. I keep to the same rule in my own timelines and find it fully realistic - the chance of a certain sperm fertilizing an egg at a certain time is so astronomical, and that even a small change is going to result in very different people being born. And, yes, although many of those people will be ATL siblings of people who were born in OTL, siblings can be very different people). Although some may shy away from this for purposes of their narrative - and more power to them for doing so - it seems that Carp is stringent on this issue; and it's his story to tell.