I noticed this as well, perhaps Fremantle have given CBBC the rights to do it in-house. They have just started making in-house animation, and had an animation pilot competition last year.
I'm almost certain this "The Duckula Show" is something different from the episode. Different writer, different year and mentions it on his website as a TV series and mentions it seperately from DM - http://www.rochellestevens.com/oswin/
Since 2008 Mark has written on a huge amount of kids comedy shows including My Spy Family, Jinx, Summer In Transylvania, Hotel Trubble, 4 O’Clock Club, The Revolting World of Stanley Brown, Strange Hill High, Hank Zipzer, Scream Street, All At Sea, So Awkward, Horrible Science and
Danger Mouse. Mark’s DM Series 1 episode ‘Greenfinger’ was nominated for the 2017 WGGB award for Best Children’s TV Episode.
He also co-created the BAFTA-winning online mystery drama Dixie.
Mark has also polished and punched up a large number of scripts for many different TV series, the most recent being The Duckula Show for BBC
and new Lionsgate feature film Four Kids & It.