Evicting Tenant Advice and Deposit...

Possession - Section 8 and Section 21

Hello, I wish to evict a tenant due to non payment of rent. The tenancy is now periodic.

I have read on the RLA website that a Section 8 is much more complicated, and should not be attempted without instructing a solicitor due to the complexity of the process, and therefore a Section 21 would prove better in the long run.

My question is that I have taken a deposit for this tenancy, and registered it through TDS. The details of which are shown below (from TDS website today)

Tenancy agreement start date 20/08/2012
Tenancy agreement end date 20/02/2013
Tenancy Status Protected
Deposit amount xxx.xx
Deposit received date 19/08/2012
Deposit protection start date 28/08/2012
Tenancy end type Periodic

Am I able to legally keep this deposit towards the rent arrears, and lawfully issue a Section 21, with the intention to persue the tenant and guarantors for the rest of the outstanding arrears once the tenant has left the property.

I am rather confused about whether I am legally allowed to issue a Section 21 whilst holding the deposit, and have been advised that I should infact return this deposit, and then I can lawfully issue a Section 21.

All advice would be welcome, as obviously I wish to operate completley within the law, and as far as I know, I have.

Kind Regards