Put the olive oil into a pot & squeeze in the lemon juice and warm up slightly. Add the olives & tomatoes and leave to one side until serving.
For the sea bass
Heat up a non-stick frying pan until really, really hot. When hot add a little cooking oil, season the fish and place skin side down into the pan.
Hold the fillets down for a few seconds to prevent them from curling up then leave on the high heat for a further 30 seconds, then turn the heat down low & continue to cook for 2 mins more.
Add a spoon of butter to the pan then flip over the fish and spoon over the melted butter. Squeeze a few drops of lemon juice into the pan & remove the fish.
For the spinach
Add a table spoon of butter and 2 tbsp of water to a hot pot, when the butter has melted add the spinach and stir rapidly until the spinach has wilted.
To serve place a ball of spinach into the centre of each plate and top with the sea bass. Finish the sauce off by warming back up and adding the chopped herbs and adjust the seasoning. Spoon the sauce over & around the fish.