I was doing a bit of reading, and wondering if there was a way to limit or avoid the Anglo-Saxon invasion of the British Isles and have Britain by and large retain more of a Celtic cultural identity. It's apparently difficult to find any good sources on when and how the Anglo-Saxon invasions began, so I'm not fussed on what POD you might choose.
I'm also not to fussed on Paganism; the spread of Celtic Christianity from Ireland can continue as normal, but basically I'm looking for a way to give the Celtic identity more power and avoid too much foreign influence, so that Britain is a wholly unrecognisable place.