Nuisance

Tenancy Types and Management

I have a tenant who is over 2 months in arrears.
I issued S8 on 14/9/06 since when I have received payments to cover rent but not arrears.
On 8/1/07 issued N5 &N119. Yesterday (11/1/07) tenant's neighbour contacted me regarding nuisance from tenant.
Should I re-submit N5 citing 'actual or threatened anti-social behaviour'?(the neighbour will give evidence).
I am concerned because the council have indicated that they will pay some arrears which will reduce arrears to less than 2 months by the time of the court hearing.
Would it be quicker if I used S21?
Thank you