You are looking at ground 1 yes?
(
Schedule 2 (17 S8 Grounds a LL can use)
But you have not quoted it in full:
“
Ground 1
Not later than the beginning of the tenancy the landlord gave notice in writing to the tenant that possession might be recovered on this ground or the court is of the opinion that it is just and equitable to dispense with the requirement of notice and (in either case);
(a)at some time before the beginning of the tenancy, the landlord who is seeking possession or, in the case of joint landlords seeking possession, at least one of them occupied the dwelling-house as his only or principal home; or
(b)the landlord who is seeking possession or, in the case of joint landlords seeking possession, at least one of them requires the dwelling-house as [F1his, his spouse's or his civil partner's] only or principal home and neither the landlord (or, in the case of joint landlords, any one of them) nor any other person who, as landlord, derived title under the landlord who gave the notice mentioned above acquired the reversion on the tenancy for money or money's worth.
”
So
1) I suspect you actually wish to use a) above, not b) (unless you derived Title from a previous landlord)
2) you can only rely on a) or b) above if you complied with the section I've underlined.
3) if you did
not comply with that, the court has some discretion ("the court is of the opinion that it is just and equitable") but to be honest it is very rare for that to happen.