The light came on But it was supposed to be serviced as part of the deal when i got it?

It was below the minimum.

Haynes said you should buy the stuff from Skoda.

Could I get some from Halfords?

As long as it conforms to "G12" spec you can get it from anywhere, I think.

how low is it?.......the OE G12 stuff is pretty concentrated and if it only needs a slight top up id just put water in, anything more than an inch though id buy a bottle

personally id get the OE stuff, VW's possibly use the same stuff i dont know

Have topped it up with water to just above minimum and the light has gone.

But I'm still going to get some from Skoda for next time we can use it for the Octy aswell;)

G12+ with a 50/50 dilution.