If I were to try and make it again ( not very good results from my last) I'd try using the juice from Lidl, 85p per litre.
Make up to 1060 and ferment with a champagne yeast :hmm:
3 grams of sugar will increase the gravity of 1 litre by 1 point.
EG. If your juice is 1040 and you want 1060, you would need to add 60 grams of sugar per litre.