Preheat your oven to 180 degrees.Drizzle the olive oil into a baking tray and then layer your thinly sliced potatoes. Top with cherry tomatoes, parsley and garlic. Place in the oven for 15 minutes.Season the fish well and then place on top of the potatoes. Layer slices of lemon on top of the fish and then return to the oven for another 15 minutes or until the fish has turned white and flakes easily when prodded.Scatter the whole dish with a little more parsley or fried capers.