For the pork chops, preheat the oven to 170C/325F/Gas 3. Preheat the grill to hot (or preheat a griddle pan to hot if the grill is located in the oven).
Score the pork chops lightly on both sides with the tip of a sharp knife, then make small cuts across the fat on the sides to prevent them from curling when cooked.
Cut one of the garlic cloves in half and rub the cut side over both sides of each chop (discard the used garlic clove).
Brush both sides of each chop with olive oil, then season lightly with salt and freshly ground black pepper. Brown the pork chops lightly under the preheated grill or brown them swiftly on the preheated griddle pan.
Make a bed of the thyme sprigs, rosemary sprigs and bay leaves in an ovenproof dish just large enough to hold the pork chops in a single layer. Scatter over the fennel seeds.
Lay the pork chops on this aromatic bed, then cover with foil and transfer to the oven. Bake for 40-45 minutes or until the pork is cooked through (the juices will run clear when the meat is pierced in the thickest part with a skewer).
Meanwhile, to make the orange gremolata, chop the remaining garlic clove very finely and mix with the parsley and orange zest.
For the creamed leeks, cut the leeks into 4-5cm/1½-2in) lengths, then shred into fine rings with a sharp knife.
Melt the butter in a wide pan and add the leeks. Stir to mix, then add the orange juice and season to taste with salt and freshly ground black pepper.
Cover and cook gently over a low heat for ten minutes or so, stirring occasionally, until the leeks are tender. Uncover, increase the heat and boil off most of the watery juices until all that remains are a few tablespoonfuls of buttery liquid.
Sprinkle the flour into the pan and stir to mix evenly. Gradually add the milk, stirring continuously, and then add the orange zest. Bring to the boil and cook for 3-5 minutes until the mixture is very thick and creamy. If absolutely necessary, add a little more milk.
Taste and season with salt and freshly ground pepper, if needed. Stir in the lemon juice. (NB: If not using immediately spear a small knob of butter on the tip of a knife and rub over the surface to prevent skin forming.)
Reheat gently, stirring frequently to prevent the sauce from catching and burning, before serving.
Just before serving, pour away any excess fat off from the chops. To serve, spoon the leeks into the centre of the plate, top with a pork chop and sprinke over the gremolata.
