It looks like this :

http://www.groby.hu/product_images/big/17709_big.gif

should I stock up on loads while I have the chance or is it available there ?

I think if it is stocked in Sheffield, then you would find it in ethnic foodshops. Try the local Chinese Supermarket, Tai Sun on Matilda street. I dunno other Asian foodstores well.

This kind of drinks are common in SE Asia area. It's very sweet though.