There's something odd about the nature of the beast itself. IIRC Wrenn went out of production in about 1992, apart from the collectors' specials, and I don't think they ever did any complete locos in the collectors' series.
The first Harry Potter book didn't come out until 1997, and the first film until 2001. Therefore it's impossible for the loco to be earlier than 1997, and highly improbable that it's earlier than 2001, unless someone was extremely lucky at guessing the type of loco and livery details. It may be an original Wrenn model that's never been used, but it's a repaint, a 'Code 3' if you go for that stupid terminology.