Hello Millimars
The powder which is used for snakes can also be bought with a scorpion deterrent.
There is a shop in Fethiye which is just opposite the D.I.Y shop(beside where the Citroen garage used to be) they sell all kinds of garden supplies. If you ask for snake and scorpion dust "Yilan v Akrep toz" in Turkish they will be able to help you. Just sprinkle a thin line of it around your property and that should keep them out.
If they are already in the garden, use a torch at night to spot them in cracks etc (they have a kind of luminous glow) and then hit them with a stick.