Identifying wine smells/behaviours/light damage?

[magick777]

In 2009, I made a pyment (a mead with grapes) using home-grown red grapes and lots of honey, of which I have one and a half gallons left, in demijohns, under safety corks (the rest having been turned into mulled wine). I've just been and racked it with a view to bottling.

Now, I have a confusion. The two demijohns, supposedly of the same batch of the same wine, smell completely different and I am not sure I understand why or what is going on here. The larger, 1-gallon demijohn smells nice, like almost finished red wine with a hint of honey. It was degassing heavily as I racked it and I have not absolutely confirmed that it has finished fermenting... I'm unsure whether to let it stand until I find out, or bottle it in pressure bottles and see what happens. Sparkling pyment could be quite interesting.

The smaller demijohn is the one that is perplexing me; it smells like old port. Not an undrinkable smell, not vinegar, kind of like strong red wine that's partially oxidised in bottle. No signs of gas or fermentation in this one, either. Which leads me to wonder what's happened to the smaller demijohn, is it likely to be worth bottling or blending, or has it gone pear shaped? Anyone know what that sort of a smell is?