Need some advice please

Hi all,

I rented my property 18 months ago and the tenants have been great, no problems, paid rent on time etc., This month they have not paid their rent and are now 2 weeks+ late. The estate agent is getting no joy from numerous phone calls/emails promising the rent tomorrow, glich at the bank, salary late etc., and the agents now feel they are getting the run around.

We are on a periodic tenancy as the 6 month st assured has passed.

Am I right in thnking that I can give them 2 months notice to vacate? I think, reading these forums, that would be the best way to go? Do I need to do this on the date the rent is next due?

The agents are suggesting we give them more time and I am happy to do this, within reason as it could well be a one off and I don't want to cause any unhelpful bad feeling should the rent be paid in the next few days.

What I want to clarify is, is it 2 months notice for the landlord on the periodic tenancy and can I only give that notice on the next rent due day i.e 25 of August and is a s21 the best way to go?

Thanks in advance for any help or suggestions