Section 21 expiry date ?

Possession - Section 8 and Section 21

I have issued a S.21 notice to my tenants due to substantial rent arrears and am currently awaiting the end of the 6 month period, which is 8th October 2021.

My tenant has advised his partner (that lives with him) is pregnant and is due to give birth at the end of September. He has asked whether they can reman in the property after 8th October in case his partner's birth runs into October and he doesn't want to be homeless with a partner &child.

I feel this is a reasonable request and I am considering allowing them to stay until the end of this year.

Does the S.21 notice have an expiry date by which time you must enforce if they haven't vacated ?

Would a decision to delay eviction have any negative implications legally with enforcing the S.21 at a later date ?