Have come across a magazine which is positive and interesting, and not full of advertising and worrying body images etc. It's called teen breathe (found it in sainsburys).
The latest edition has a section on perfectionist tendencies, and another on how not to always follow the crowd. Not patronising or preachy, but food for thought - it seems to underline some of the messages I am trying to get through, but maybe they have more credence in magazine format.
Am not linked to the magazine in any way but wish I'd known about it earlier, so just posting in case it helps someone.