Trivia

At an sf/media convention in the US, Leeson anonymously entered a "K9 Voice Imitation Contest" and came in second.

Along with Peter Davison and Elisabeth Sladen, he is one of only three actors to play the same character (K-9) in both Doctor Who (1963) and Doctor Who (2005).

Along with Elisabeth Sladen, he is one of only two actors to both appear and play the same character (K-9) in four different television productions based in the "Doctor Who" universe: Doctor Who (1963), K-9 and Company: A Girl's Best Friend (1981), Doctor Who (2005) and The Sarah Jane Adventures (2007). He appeared with Sladen in all four.

He appeared in K-9 and Company: A Girl's Best Friend (1981), the first television spin-off of Doctor Who (1963), which featured K-9 as voiced by Leeson and Sarah Jane Smith as played by Elisabeth Sladen.

Along with Elisabeth Sladen, Tommy Knight, Alexander Armstrong and Lachele Carl, he is one of only five actors to play the same character (K-9) in both Doctor Who (2005) and The Sarah Jane Adventures (2007).

One of about 37 performers to have acted both in the 20th century Doctor Who (1963) and 21st century Doctor Who (2005) TV series.

Was a continuity announcer on Channel 4.

After joining the Leicester Dramatic Society, he won a place at RADA.

Served as a Justice of the Peace for over 25 years, having acted as deputy chairman of his local Bench - Ealing - for six years.

Member of the Association of Wine Educators and Circle of Wine Writers, having trained at the Wine and Spirit Education Trust.