For a good quality grape juice without added Vitamin C, try "Lloyds" Grape juices. For a list of distributors visit his website;
We have been juicing watermelon or apples and pears, when fresh these seem to cover the taste completely.
As far as other fruit juice goes we have found 4 good ones;
1 "Rosie's" crushed cranberries, blackcurrant and apple juice in the cold section of the super market
2 Pomegranate juice by Bickfords also in cold section I think.
3 Pear Juice in a tin on the shelf by Golden Circle.
4 An organic apple juice from Coles called "Pure harvest"