I had a similar situation with a short rent.
Basically on leaving I was to be charged for cleaning plus a small damage to the back of a door.
I pointed out the poor condition on the incoming inventory and the fact that I had during my tenancy cleaned up mould, dust and marks. The cleaning part was refunded.
However, the door damage was noted as two marks on the incoming inventory,
whilst on the outgoing inventory one mark and one damage was noted.
I know I did not cause the damage and it required close inspection to realise the door veneer was slightly indented and not a mark (about a one inch circular indent).
I did go to court but lost (small claims court). Basically, the judge has to apply the law, even if it may seem "an ass" at times. What I had not expected was myself against three witnesses!! Who were they? The landlord, the landlords husband and the letting agent!! Of course they all had the same story and under oath stated the door was not damaged at the start of the let. The Judge sees three witnesses under oath vs one claimant under oath. In fact, the Judge believed I was telling the truth but ruled on the balance of probability and I lost! The letting agent did get some terse words from the judge as the tenancy contract did indeed contain very unfair terms (that was upheld by an earlier complaint from myself to OFT).
Basically, if you are renting take photos of everything like marks, stains, damage and make absolutely sure it is on the incoming inventory. My outgoing inventory included things like spiders webs, small splashes (about 1-2mm in diameter!) on the kick space. It was clear to me they viewed my deposit as extra income.
All in all it cost me a couple of letters, £30 in the small claims court plus £99 loss of part of the deposit for a new door (I doubt if it was ever replaced as the door functioned as it should!!) and half a day for court appearance.
For the defence, well both the landlord and her husband spent time at court, plus the agent had two persons present (one witness, one as support).
Even though I lost, it was worth the effort - some tips:
- Keep a record of all exchanges with dates and times.
- Photograph everything that is disputed (indeed insist that you can revisit the property with a witness of your own to get your own photos of the disputed items)
- You MUST try to resolve the dispute with the landlord and letting agent first. Write a letter explaining the facts and keep to the point, emotions and opinions are not helpful (OK you may feel better but they really are of no use). Set a deadline for a response (eg 14 days).
- If you are still not satisfied, start reading about a small claim here:
Making a Claim
Court clerks can help you fill in forms, but they will not and can not advise you, they are not your solicitor or legal adviser.
Having said that, I found them to be helpful and courteous.
- Again fill in court forms with facts and keep short and to the point, as I said earlier, emotions and opinions are not helpful and the judge will ignore them - he is just applying the law as it stands. Include photos, even a plan of the rented property - this will help the judge understand any detail.
- How long will all this take? Well expect months not weeks.
And one last comment, I abandoned renting and invested in a second property. I now rent that property so I'm now a landlord and can see things from another point of view. I concluded that landlords get away with keeping part or all of a deposit because most people are nervous about challenging, especially if they are offered part of the deposit back "as a carrot".
If you know you did not cause damage, stick to your guns.
I actually believe in being fair and reasonable as a landlord, but yes I do expect rent as agreed.
I don't agree with large penalties if rent is late by a few days on one occasion, everyone makes mistakes or has a late pay cheque. Repeated lateness however becomes a problem, I expect my tenants to be fair and reasonable to me also. The best approach is to keep the landlord and his agent informed if things go wrong with payments.
I hope that helps - do not be nervous about challenging, but do remain reasoned and courteous. Be prepared to do a bit of reading and research. And remember, the deposit is your money, not the landlords unless you have proveably caused damage during your rental.
More help on Unfair Terms in Consumer Contracts can be found here - there is a small guide for tenants and can be downloaded - check the points against your rental agreement:
Unfair terms guidance
Good Luck
Dispute - Regarding Amount Taken Of Our Deposit 
Galliath battle
