I would do one vine per bin, and make sure it has regular watering, and regular feeding with Growmore, or suchlike. I would also make sure that the bin has holes in the bottom for drainage. More info about exact symptoms is needed for more specific diagnoses.

I wonder why in a bin? Or are they under cover? A vine is easy to control if you want to limit it's growth by pruning and shortening. What are all those stumps in the fields in France but grapes under firm control? I suggest you free the poor vines from their bin and all you would have to do is prune and pick when they have their roots down outsjde whether indoors or not.

Some folks have little but pavement in their yard, and a bin is a cheap way of getting a big container for a desired plant. I understood his or her complaint to be that it wasn't growing enough, which is easy enough to happen in a container without regular feeding and watering, and with poor drainage. Lack of sun can do that, too, if in a narrow courtyard.

Thanks guys will give it some thought, cheers