delay in return of the deposit

Tenancy Deposits

Hello,
how long landlord can hold deposit after the tenant has moved out? In this case all the bills have been paid, but there's a possibility that there has been some damage. The problem is that landlord is away and is not able to visit the flat to estimage the cost until later date (2-3 months after the end of tenancy).
In other words is there a deadline after which the deposit has to be returned in full regardless whether has been any damage or not?
Many thanks for your advice!