Section 8 notice - do I serve another one?

Tenancy Types and Management

I served a Section 8 notice on my tenants on 12th December 06 saying court proceedings would begin on 2nd January 07 using grounds 10 and 11 (but not 8 as they didn't owe 2 months rent at the time but they will by 2nd). I thought that would be enough to scare them into paying. It hasn't!
If I were to issue N5 and N119 and by the time the court hearings begin ground 8 also applied would the judge HAVE to make an order for possession if it wasn't specifically on the original notice?
(Do I have to start again on 2nd Jan with a Section 8 using ground 8 as well as 10 and 11?)