The Hydrometer reads 1 when sat in water (I have 2 and both give the same read)
I was making the one that you talk about with some slight changes (well quite a few)
(2 cartons of Ocean spray cranberry and blueberry, 1 ltr of blackcurrant high juice, 1 ltr of summer fruits high juice, 2/3 of a bottle of Oasis (full sugar) 333g Sugar and all the others required.)
The only other thing that I can think of is that it is not warm enough (dam combi boiler means no warm cupboard)
Any ideas?
Start again, because:
1) 2 x Cranberry & Blueberry possibly does not contain as much flavouring as you'd get from 1 x Cranberry & 0.67 litres Blueberry (but point (3) below is more important).
2) You have overdosed on sugar as carton juice contains around 110g/litre (except grape juice) and high juice approx. 495g/litre, meaning you have over 1.5Kg of sugar in your wine excluding the Oasis (whatever that is), when I aim for 1Kg/gall.
3) Summerfruits High Juice (the concentrate rather than the chilled ready to drink stuff from Morrisons) does not make good wine and will impart a harsh unpleasant flavour that will not go after years after maturing.
My recipe specifically excluded using anything containing preservatives, thus avoiding any chance of the fermentation being hindered, but assuming you use the boil method to drive them off first, my best guess what's happened is:
The sugary high may have sunk to the bottom and the sample tested was taken from the top. The amount of sugar (any any residual preservative?) has hindered fermentation. When fermentation has eventually started in the upper level, any sugar fermented has been replaced from the syrup in the bottom - so you get bubbles but not drop in S.G. from a subsequent test.
Stick to the recipe and it will have finshed in around a month and be clear and ready for a taste(s) in two.