The following is NOT advice(legal or otherwise) but is just FYI:
The TDS basically view the deposit as the tenants money and the LL has to prove damage or loss
greater than fair wear & tear if they are to claim anything.
Sounds like you don't have a detailed original Inventory which should have been signed by you at the time of check-in.
Without that how, is the LL to prove any damage?
If you have a dispute with the LL and the LL can't prove damage then the TDS will most likely award you the
majority of the deposit or all of it.
If there is a dispute, only the disputed amount of the deposit should be held back until resolution.
And although helpful, contrary to popular belief photos & videos come a distant second to a signed written detailed
inventory as far as the TDS adjucators I've spoken to are concerned, but be prepared to take them if the Letting Agent
points any damage out to you during checkout, you should get a signed copy of the checkout report but don't sign it
yourself if you disagree with it.
Also fair wear & tear can vary if the LL knew there were children, pets, smokers, students etc then assesed wear & tear is
greater than if someone lives alone and the LL is supposed to have covered this extra wear & tear
in the greater rent that should have been charged.
It is quite an involved task to accurately cost out and apportion any liability to tenant and each case is obviously
different but from your description it sounds like most things were past the reasonable lifespan and so the
Letting Agent would have a hard job making the case for deductions.
Be interesting how you get on.
Professional Independent Inventory Provider
www.accord-inventories.co.uk