You say the tops are flowering, but you don't mention foliage - is the foliage only present at the top as well? If so they must look awful. First, remove any obviously dead wood, see what you're left with, then once the flowers are finished, prune back to a better shape. If you cut them right back, you may lose them, but as they look so awful, there's no choice. And you can always replace if necessary.

Thank you, will give it a go and see!