Yes, not only was he Welsh but a native speaker of Welsh too. He is Wil Cwac Cwac there. The programmes were created for Welsh speakers but such is the revival in the language that there seems no doubt that the videos sell largely to parents, usually anglophone Welsh themselves, who wish their children to learn it. Certainly I did not find the videos in English, only Welsh, when looking on the web e.g. Lastminute.com