Preheat the oven to 220 C, Fan 200 C, Gas 7. Place the potatoes, stock or wine, olive oil and garlic in a large ovenproof dish. Sprinkle over the salt and a generous grind of black pepper.
Add the oregano, bay and spices and squeeze over the juice from the lemon quarters, then add the quarters themselves to the tin. Add the tomatoes and cover tightly with foil.
Bake in the hot oven for 20-30 minutes then reduce the heat to 180 C, 160 Fan, Gas 4. Remove the foil and continue to bake the potatoes for a further hour until they are soft and have caramalized in places, but are still sitting in a bit of juice to pour over. Serve immediately.