Perfect thank you!I would start with a colour remover. Then you will need to lighten your hair to as light as you can get it. It's doubtful that a level 10 will be achieved. If you aim for a clean level 8 then tone with violet to completely neutralise any yellow. This will give you a clean, clear base to apply the blue. A semi permanent would be the best option for achieving that blue and it will make it easier to maintain.