I have had the gun in my hands .
It is the trigger release .
Made in Italy by P&V from parts supplied by Purdey then returned to England for assembly & finishing by Purdey .
I detect a smattering of journalistic licence actually . Why would you manufacture all the parts in London , ship to Italy , ship back and then assemble and finish????
More likely using Italian skill and expertise and the necessary machinery , then applying a premium pricing structure.