Evicting a tenant for antisocial behaviour

Possession - Section 8 and Section 21

Good morning, I hope all are well. This is the first time I have posted on here. I would Really appreciate some advice as I am very stressed. I will be contacting citizens advice tomorrow and have  put an online inquiry in, But wondered if anyone had had a similar experience to me.

I have an HMO, which has been working very well with happy tenants until the latest arrival.  Unfortunately, after having tried my hardest with this  tenant, I had to serve a section 8 on them yesterday due to their extreme antisocial behaviour. They have been causing the other tenants extreme distress. As I used ground 14 along with 12 and 10, in the section 8, I gave 24 hours notice, but the tenant is saying he cannot leave because he has nowhere to go, saying he will have to go down the court line. I take it I have to fill in a standard N5 form. Is that correct? Not the accelerated  N5b? Any advice would be most welcome as I am very stressed about this, having never been in tnis situation.  Many thanks