Tenants rights after lease lapsed for two years..???

Hi, I wonder if anyone can advise me on tenants rights when a 12 month lease/contract has expired over two years ago. I have the same tenants for the past three years and have never had any problems.
We had a lease for the first year and when this ended.. for various reasons, mainly complacency, the lease lapsed. I now wish to enter a new lease with the tenants and they have no problem with this.
Is there any special clause I need to put into the new contract to cover these missed years or are there any issues with squatters rights...??
Tnks.

You need to check out check out www.prtb.ie

Im guessing you arent registered there. It will explain about tenants rights etc... leases really dont hold all that much power. possesion of your front door key affords a rent paying tenant plenty of rights.

http://www.prtb.ie/act.htm

Thanks yankinlk,
I am registered with prtb, Will contact them to get advice...