The Celts were not responsible for Stonehenge, were they? There was[were] a prior indigineous populationin Britain.
I'm sorry, but you really need to look at the research published over the last couple of years. You might be unaware of the migrations that occurred in the middle mesolithic period and the stability of the gene pool since that time. If you are speaking of language and customs, we have little argument. But language does not necessarily make one Celtic just as my speaking Mandarin does not make me Chinese.
If your family resided in Europe in the early 19th century, the likelihood is that there is some Celtic influence in your DNA...just as there is likely to be some Neanderthal.
The BBC reference is more for the lurkers who don't see the need to enter the conversation.
I have acknowledged those prior indigenous population several times. I even provided links which substantiated that those populations existed before the Celts settled in Ireland. I have never disputed that because I'm pretty sure that there was an indigenous population here in this very country which was supplanted my migration. Unless we follow your logic that indigenous populations prohibit new migration and we have to undo centuries of human history and dissolve the United States.
What I have disputed is that a pre-existing indigenous population prevents future migration by other populations. You cannot seriously claim that on the one hand that DNA samples from Ireland have been stable since that time and then admit that there is Celtic influence in modern Irish DNA from the Iron Age. Those are two incompatible views.
I do not see anything productive in spending any more time discussing this with you. You may hold what beliefs you see fit.