Hi Nicke,
to my opinion,that is not S.petrii.petrii look totally different...
the picture is bad but here is one petrii i used to keep.
in petrii,the tail is whip-like,ground color and back pattern are different.etc...
i'm pretty sure of that.
yours looks like a kind of Stenodactylus sthenodactylus.
i wouldn't go for a S.doriae .
how big is it?
Pierre