Cut the leek into thin strips. Bring the water to the boil in a pan, add the leek, lentils and salt, bring to the boil then reduce the heat and simmer for approx. 5 mins., stirring occasionally, until almost soft, drain.
Combine the mustard, vinegar and oil in a bowl. Finely chop the thyme, add to the dressing and season. Add the lentils and leek, mix together, cover and leave to infuse for approx. 30 mins.
Season the scallops.
Cut the slices of ham in half lengthwise. Wrap each scallop in half a slice of ham, secure with a toothpick. Heat the oil in a non-stick frying pan and fry the scallops for approx. 3 mins. on each side, remove from the pan and remove the toothpicks. Plate up the salad and scallops, garnish with thyme.