its possible the heraldic “lions” may well be leopards, puma, or even the Lynx which certainly can survive in the UK.
in them days before cameras and long lenses were invented and people often got eaten by creatures in the woods artists probably thought it more prudent to keep a wide berth from big cats, and draw them from memory later..
A Lynx was found randomly sat on a wall in Cricklewood in around 2001, it was taken to London Zoo and eventually transferred to France.
