Sending notice by registered delivery

Hi

I posted a section 8 and section 21 notice few days ago to my tenant. I sent the notices via registered signed for next day delivery. Unfortunately, Royal Mail website is not showing anything. It seems has if the notices have not been delivered.

I also hand posted copies of the notices in front of two witnesses through the tenants letter box. Is this sufficient as a proof or should I resend the notices by signed for post again?

If resend the notices by post then should they be dated the original date or today's date?

Thanks for help