Mr Bean - The Animated Series

A follow up from the Mr Bean series.  In an episode called “Missing Teddy” Mr Bean forces a Reliant Regal Supervan to drive into the back of a removal van. Later, Mr Bean then goes to the police station to put up a Missing Teddy poster; One of the other 'missing' posters in the background features the Reliant Regal.

Cars 2

In the 2011 animated film Cars 2 by Pixar two of the main characters are 3-wheelers.  The first is a 3-wheeler called “Tomber” which is apparently a little French car (Tomber meaning to fall)  though appears to be styled on a Reliant Regal saloon with Citroën DS headlights

Never Say Pink Furry Die

This 1992 Aardman Studios animation about a women who wakes up with a hang over after her hen night features what looks to be a Reliant van.