Ok - so I have changed the Microsoft setting to None which means my child can not download anything from the Microsoft store.
On checking this, by going into his user account that I have set up for him, I find that all downloads are being blocked - paid and free - except facebook - which actually is one of the main one's I do want blocked and unavailable fro free download? I am sure I'm not doing something wrong because all others are blocked... so why is facebook still allowed? Any clues anyone please?