As far as geographic POD's go, having Antarctica end up in the south Pacific is ASB, having a 50 mile wide stretch of land raised 200 feet in elevation is no more ASB than having typhoons not sink the Mongol fleets heading to Japan.
As has been said this is fairly late into human development and so would not stop the ascendancy of homo sapiens. In fact, if Ireland is still separate I don't think you see too much variation until a few thousand years ago. You're most likely going to see the isles still populated with Celtic tribes, though with a higher population earlier. This would probably encourage more Brythonic Celtic immigration to Ireland precluding the Gaelic settlement later. You'll also have increased contact with the mainland. Expect to see a "tin road" akin to the silk road spring up from Cornwall to Calais, up the Rhine and down the Danube towards the Middle East pop up in the Bronze Age.
I think you might start to see big differences pop up around 1100 BC or so as the collapse of trade routes at the end of the Bronze Age will look rather different with the Mediterranean not being the only viable source of tin. I don't think the collapse would be prevented, but possibly delayed. From this point on, it becomes harder to speculate.
The Eastern Mediterranean probably stays largely the same but it might be possible to see northwest Gaul develop a more coherent society earlier and see a unified state emerging before the a Roman-like expansion can absorb the area.