Ok I have already answered my own question but I have a new one....why?
I had to go to the admin / beta features and inspected with my chrome dev tool to find the liquid option was hidden.
Once disabled the css I could select and turn on Liquid.
But my question is why was it like this?
Can't be me as I have other sites with Liquid displaying.
Its Beta features and they are only for parters and partner accounts.
So under a free site these are options, like some others (you probably not see develop tool) are not available to such sites. But being a partner account if you access a free site or someone else's site etc if you know a url and so on you can access such things.