Deposits should be held by an independent body . Also Landlord cannot demand new Carpet at best as you say depending on age etc etc
Time tenants took on Landlords
I help them do that in my spare time Ian, we usually win, in the fact that the Landlord does not get to keep the whole deposit, or get betterment. by law since 2007 all deposits are meant to be held independantly in 1 of 3 schemes, however only 1 of the schemes actually involves the landlord giving the money to a 3rd party, the other 2 are insurance schemes. At the end of the day if the landlord refuses to give back the deposit or authorise the release of the deposit in the case of the DPS (deposit protection service), then it involves court action. If the landlord has not got an inventory from when the tenant moves in (a lot of the times they have not) then the Judge always grants the whole deposit to the tenant. It can get complicated, but if a landlord is trying it on, or scamming, then the letter before action for the return of the whole deposit, or deductions of provable damage not including wear and tear, usually does the trick.
There is no recompense at the moment for claiming against a landlord who does not protect the deposit in one of the 3 schemes, as the landlord can put it in the day before a hearing if so inclined and the judge has to throw the case out.
The landlord although able to claim large amounts for repair if damage is proved, does not in fact have to have the repairs done, however it is a bit naughty for him to try to charge the next tenant for the same damage. Hence the need for a full inventory, BUT if there is not an inventory it is in the tenants best interest NOT to insist on one, as the landlord will be unable to prove any damage at the end of the tenancy.