And if so where would I define it?
You would define it in a tpl file of your choice depending on where you want the
Is it not possible to define this once as a language variable within cs-cart back end
Will appear as
2. Not sure what you're asking because I don't use options or "in stock - yes/no"
3. Once you define the language variable in admin, any changes to it will be reflected where called with:
Thats great Matt - it doesn’t mean much - at the moment - but it will have given the start point that I needed to then look at it without drifting around in a random way.