Getting away from the Meteor a bit, I remember a cunning mod to the Goblin fitted to our Vampire 5s at Tarrant Rushton (1953). Some aircraft had experienced trouble with the aneroid capsule of the barostat sticking resulting in constant rpm. At high altitude this would be at high rpm but the subsequent descent with an unresponsive "go lever" could be embarrassing. So a little hammer was attached to the barostat with a button on the right cockpit wall which when pressed would tap madly on the gubbins and hopefully free the offending bit. The engineers explained that it had never been a requirement on piston engines as the whole thing vibrated anyway.