Tesco sells walnut oil. Look for smaller sized bottles near the olive oil. Keep it in a cupboard and don't let it stand in sunlight and keep an eye on the use-by date.
When you are buying an avocado, press gently with your thumb at the top where the stalk used to be. It should give a little. If it is too hard, it will ripen up at home, so don't worry. Don't store whole ones in the fridge, although once you have cut one in half you should store the remainder in the fridge, wrapped in clingfilm. If the other half does go a little brown, it doesn't matter, it will be OK to eat.
When you are buying an avocado, press gently with your thumb at the top where the stalk used to be. It should give a little. If it is too hard, it will ripen up at home, so don't worry. Don't store whole ones in the fridge, although once you have cut one in half you should store the remainder in the fridge, wrapped in clingfilm. If the other half does go a little brown, it doesn't matter, it will be OK to eat.