Oh dear.
All I can say is that I'm glad I don't have a TV set and therefore don't need a licence.
I've seen the clip of this and my thought was - Merlin goes to Hogwarts.
Everything about it is wrong. The period is wrong - Merlin and Arthur were around during the Dark Ages - NOT medieval times. There weren't castles then as most of the castles in Britain were built by the Normans (to protect themselves from the Scots and Welsh).
And the castles in the clip are quite obviously NOT in Britain.
Don't get me wrong - I'd love to see a decent series made about Arthur and Merlin (even if it is unlikely that the two ever even met) but this is just Saturday evening fantasy for the kiddies.
I hope I'm wrong and it's really good - but the BBC made a complete balls up of Robin Hood and I don't suppose they'll do any better here.