How much longer is the 2-stage Merlin than the single stage Merlin?

The question could be put another way – how much longer is the nose of the Spitfire Mk.IX than that of the Spitfire Mk.V, after allowing for different spinners? I’ve looked in several sources, but have not found an answer. Paul Monforton’s book provides dimensional data for just about every structural detail for the Mk.IX, but only the Mk.IX.