I wondered if there was legislation to suggest that fire door closers should be fixed to the inside of a door rather than the outside. I have had a closer fixed to my door on the outside. I have not seen this before so I wondered if this is the correct fitting. I am on the 22nd floor of a tower block and my door leads into the communal hallway.

I was also concerned that this may allow someone to prevent me from opening the door from the inside (unlikely- but a possibility). 

There's no legislation on whether the self-closer is fitted outside or inside. The usual reasons are because there's no room on the inside (because of a bulkhead for example) or because the building owner/operator wants to check each door has a self-closer without having to look inside each flat. Generally overhead self-closing devices work better fitted to the inside.