Do I need to provide a gas safety certificate after my lease ends?

Hi, I decided to rent my property through one of these guarantee rent agencies (who have contracts with the local council).

I entered into a lease agreement with them for one year with the end date being the 5th of June. I also provided them with a gas safety certificate that ends on the 5th June.

I gave them 3 months notice that I no longer want to continue to rent through them and that I want my property back, however it seems that they have no intention of giving me the keys back on the 5th June arguing that the council still need to find another property for the tenant as it can’t make them homeless.

Now they are asking me to provide them with a new gas safety certificate that covers the property after the 5th of June.

My question is do I have a legal obligation to provide a gas safety certificate beyond the date of the lease agreement when I made sure that I notified them (as per the T&C of the lease) that I want the property back by the 5th of June.

Any suggestions will be gratefully received.

Thanks,

Defrim