Right, now getting back to the original question. Stig may be talking of racing, in which case there would be a metal floor (allowing some heel movement) rather than carpet (which would cause the heel to stick).
t may be that he only pushes the clutch far enough to separate the clutch plates and not to the floor. This is often favoured among professional racing drivers as it helps with rapid gear changes. Those who knew John Lyon and John Whitmore might remember they both advocated this technique. Possibly the only thing they ever did agree upon.
If pushing the clutch pedal all the way down it usually requires allowing the toes to flex backwards at the fullest extent of clutch travel. The toes come into play and not just the ball of the foot. Try this to see of it works for you. With the engine off experiment with foot placement on the clutch so that with a fully depressed clutch the toes are flexed towards you. Place the heel down and see if you have sufficient flexibility in the ankle to bring up the clutch all or nearly all of the way up.
When we taught learners to hill start we would get the learner to set the throttle, slowly bring the clutch to the bite (I think I got the spelling right this time
) point, hold it there, place the heel down, then slowly bring the clutch up with extra throttle. The idea of the heel placement was to help control the clutch through the plate engagement process.