Very possible, maybe even probable. I've read that the Brythonic Celts entered into Britain via Gaul -France. There was a sizable Celtic settlement (s) across the channel for hundreds+++ of years. Some say they were P Celts associated with the Brythonic Celts of Wales & Britain; others say Le Tene. Easily could have been both. Both were known to have migrated into Britain. The La Tene are said to have migrated into Scotland & Ireland as well.