Landlord taking deposit yet no inventory?

My landlord is proposing to take a third of my deposit now that I've moved out of my flat for things such a walls scuffed and need repainting, flat dusty and dirty. He claims that the inventory company used has performed a check and come to this conclusion, although no inventory check in was performed that me or my flatmate were present at, and we havent signed anything to acknowledge the original state of the flat. Furthermore, we cleaned it top to bottom before we left and left it in a far better state than we found it in, these scuffs and marks on walls etc being present before we moved in. Our deposit is part of the Tenants Deposit scheme and we want to contest the amount he wants to take, do we have a case based on the fact that there was no inventory check in (and to be honest dont believe there was a professional check out either)?