Leveling old patio

[NotebookNewport]

Hi
I have a small patio made with 600mm square stones. This isn't that flat in places and I was going to recover it with click together ikea decking tiles. The question therefore is there any self levelling concrete type stuff that might prove suitable?

Thanks

 

[Crystalclear]

Question is, why are they not flat? Is their movement? That would need looking to before you start placing anything above or on top.

 

[NotebookNewport]

sorry for the delay - its been down about 20 years - no rocking / loose stones, just not flat