As with Happy Monster Band, Maggie and the Ferocious Beast and Max & Ruby, Wow! Wow! Wubbzy! was redubbed for the UK market. The dub is known to have Janet James as the titular character. It is also known that Kooky Kid uses the term "crazy" in the British dub. Also, according to Gilby1385, the voices of the Wubb Girlz and the Wuzzlewood News Reporter were unchanged in the UK dub.
The British dub was taken off Nick Jr UK around 2012, and the only UK Wubbzy DVD available is Wubb Idol, though that DVD uses the American dub.
The series is available on Amazon Prime Video in the UK, but they're all the US dub episodes.
Findings
Part of the British theme song can be found on an old Nick Jr 2 video, alongside an episode which uses said dub. And there is also "Home Is Where The Heart Is"
Known Voice Actors
Wow Wow Wubbzy
Wubbzy - Janet James
Widget - Julie-Ann Dean
Walden - Wayne Forester
Daizy - Lynn Cleckner
Crazy/Kooky Kid - Janet James
Buggy - Janet James
Huggy - Julie-Ann Dean
Muggy/Earl - Wayne Forester
Moo-Moo the Magician - Wayne Forester
Chef Fritz - Wayne Forester
Home is where the heart is
The undubbed song
Postman/Mailman - Wayne Forester
Madame Zabinga - Janet James
Old Lady Zamboni - Janet James
Shine - Beyoncé (Retained from the US dub)
Sparkle - Grey DeLisle (Retained from the US dub)
Shimmer - Tara Strong (Retained from the US dub)
Jann Starl (Wuzzlewood News Reporter) - Jann Carl (Retained from the US dub)
Updates
1/1/21
Someone has found footage of the UK dub. Here is the link. Wubbzy UK Dub - Google Drive
Wow! Wow! Wubbzy! - Theme Song (UK English)
Partially-dubbed Theme