The LOCI website notes there was a Mk1 Morris 1800 (E reg) that featured in the Professionals in the late 70s / early eighties. The episode has now been added to Youtube and there are shots from both inside and outside the car from around 5 minutes to 15 minutes.
Ford were certainly on the ball with Capris, Escorts and Cortinas used and placed strategically everywhere in this series. Another example of BMC/BL failing to promote their more advanced (in my opinion) products, not having learned from Z Cars and the Ford Zephyr/Zodiac success a decade earlier. (Apologies to non UK and younger readers who may not have heard of these popular UK TV series.)