I now know the exact name of this Berberis Clump, I found the original label buried in the root mass when I was giving it a clear out a few days ago.
This was it before clearing. I just wanted to remove excess mix from the pot and some of the old garden soil and aerial roots from around the base.
After the clean up I have uncovered about an extra inch worth of base.
Look forward to getting this one into a smaller more manageable pot next year.