Classic stalling cure

OU may remember I’ve had a slight issue with the idling of my Range Rover. It was absolutely faultless on the family holiday to Cornwall last year, covering 500 miles and returning just over 20 mpg. But, probably from September, I’d had a problem where it would stall, typically at junctions and traffic lights. I’d be at a steady cruise, brake to a halt, the revs would drop, the car then barely tick over and the engine would die. A month later, it began misfiring, clearing itself over 3000 revs.