Q.I Have Received As A Present An 80cm Miniture Olive Tree. Should I Pot It On?
What size pot should I use, its currently in an 18cm high pot.

Certified GKH Gardening Expert
It is ready to pot up when you see roots coming out of the drainage holes, or the roots start to curl around the container. The tree's rootball will come out in one piece.
If it is ready to pot up a size, then only go up to a container that is 5-8 cm larger on all sides.
This will help you:
https://www.gardeningknowhow.com/edible/fruits/olive/growing-olive-trees-in-containers.htm