You could always back sweeten with a little honey. I had a batch a while ago which turned out like that (turns out I'd used too much yeast by mistake), but after the extra honey, it came out delicious!Obviously campden and potassium sorbate too ;-)
mmm, maybe could be the extra yeast dose... I put in 2 7g packets... Could it be due of that?
About the backsweeting, how much honey/sugar should I add to get something edible?