I'm sorry for the confusion, I don't think i've made the situation clear!
I do indeed need the variable to be for the web user's session.
Reason being is that when they go to an affiliate form of mine (same domain but outside QA), I want that session variable to be available to add to my form field.
So browser views question.
If an editor has answered the question (ther will be only one editor for each question although other usertypes may answer), his username gets added to the php session array as eg ['answerer'].
If browser then visits my webform outside QA, then $_SESSION['answerer'] is available to it.
Hope this makes a bit more sense?
Solved by using raw: