Let to friend- what's bare minimum documentation?

[Snorkerz]

Yes ('principal').
The idea is that an owner-occupier wishing to let on AST/SAT can reserve in advance the right to recover the premises, just as in s.21 but with no time constraints re Notice periods- although neither procedure can result in a Possession Order that operates earlier than expiry of the Letting Agreement's fixed term.

Can you clarify?

Both s21(1)(b) and s8g1 require 2 months notice, and neither procedure can result in a Possession Order that operates earlier than expiry of the Letting Agreement's fixed term.

Whilst an s21(1)(b) can not be served before the commencement of a tenancy, a s8g1 can not be served after.

[jeffrey]

Yes. Because any g1 Notice is (= ought to have been) served before the Letting Agreement begins, L has nothing further to serve before beginning possession proceedings. There is no 'Notice' period, unlike re s.21 and the ongoing LZ discussions re the point at which L can:
a. begin proceedings;
b. have a Court hearing; and
c. obtain a Court Order.

Also, of course, the 'six-month' rule does not apply if L is using g1.

Finally, g1 does not 'require 2 months notice'. You might be thinking of s.8(4A)(a). When it mentions that period, it speaks of a s.8 Notice using another ground + g1; by definition, a Notice on g1 alone that is served pre-letting will have been served two months before proceedings (unless the fixed term is shorter than two months!)

[jta]

Yes ('principal').

Not my mistake! To write principle when I mean principal would go against my principles, it came with the cut 'n' paste.

I was really careful with that last bit.