Poor quality wine

Hi,

I have been making wine on and off for a few years, my best was a batch of bramble wine around 6 years ago.

I made a batch of goosberry wine red and white 3 years ago and it's rather yuck.

The white is sweet and the red is very very dry but both are like rocket fuel.

Can i referment the white to take away some of the sweetness and if i add more suger to the red will it still be drinkable or will it begin to referment?

Ha Ha, i did think about that but i wrecon i'd just end up tipping the lot down the loo.

I have tried to referment the white before but with a standard wine yeast but it doesn't start.
I was thinking of using a champagne yeast as these ferment out to a higher % but not sure.

As for the red im deeply dissapointed as it has a very good base floavour but is sooooooo dry almost acidic.
I't not turned vinigary, i have had one go on me and that was awful tasteing, i could drink the red but i wouldn't start to enjoy it until the 3rd glass 

I don't like mixing wines.
The reason i make them is so i can taste the fruit that their made from and decide which is best.

I think i'll sling the red and try re-ferment the white with champagne yeast.
Just wondered if anyone had done it before.