Privet lollipops

Both are put away in the Winter as the wind blows them over in their pots. They are in large pots, ceramic. 

Over the years they have had damage from birds nesting inside them and then the insides of the balls lost their leaves and the stems started dying. So I cut them back, hard. Then I neglected them, unavoidable. They got leggy and mishappen and I seem to be always trying to get them back to some round shape. But the inside has still not grown and is gappy. I can not find any white in the soil but I can not see very deep. the roots are only 1-2" below the surface. I did try last year to remove it from the pot, but was on my own and it wouldn't budge. I have fed it a little from time to time. I keep it watered regularly, except over winter. I have put it back outside as it looks so rubbish.