Did you know it was an adaptation of a book by Allan Ahlberg? It was my very first exposure to the sensation of "Well that's not how they did it in the book!". The pilot movie is the adaptation of the book and as far as I recall, an effective one with changes mostly to allow for continuation as a series.
Oh and one episode had a girl who like Troll dolls getting wedding jitters before marrying Jason Orange from Take That!.
I can't quite remember much else.
I remember that show!!! IIRC, everytime the main character was about to transform, he'd scratch his nose, or something... Still remember the theme music, too!! I only remember two episodes well: one where he was confused with the throne heir of some country, and another where we find out his grandma or aunt has the same condition... and I remember that there was some sort of network of tunnels allowing him to get into some girls' room in his dog form... Aaah, the memories^^
Let me explain! ...No, there is too much. Let me sum up!

I just made a page for the 90's British series Woof!. Problem is, being an American my only exposure to the series is the Pilot Movie, which I had on VHS as a kid and haven't seen much since (and which, until I started making the page, I was only vaguely aware was a Pilot Movie and not stand-alone), Wikipedia, and a few clips on Youtube of the rest of the show. If any of you British tropers out there have more of a perspective on it I hope you'll contribute to the page.
And hey, talk about the show as well. I fondly remember the movie as being full of charm and one of my favorites when I was a kid.