Hi Mark,
Sounds like Clapton may just like this new variety. My 2 are very all or nothing, they will either clear the plate and ask for more or turn their noses up after 2 mouthfuls.
I do find myself saying no to them if they are continually asking for food as Jack has a slight tendency to obeseness, although he is not obese at the moment.
Best advice I can think of is to keep an eye on it and see. If he keeps eating loads it may be worth asking the vet.