Don't worry. It was your landlord's (or his agent's) job to compile the inventory and to get you to agree it, not the other way round.
Without an agreed inventory, or any evidence of the state of the property/contents when you moved in (and when you moved out), he will struggle to claim anything at all from your deposit. The burden of proof is on him, so you should be fine. If he does try to claim anything, simply dispute the deductions, present your own evidence if required and let the scheme adjudicator decide. (I take it your deposit is protected?)
'Pause you who read this, and think for a moment of the long chain of iron or gold, of thorns or flowers, that would never have bound you, but for the formation fo the first link on one memorable day'. Charles Dickens, Great Expectations