With such scant information about Drest, this detail is enticing:
In the ancient graveyard of St Vigeans in Forfarshire, within which there exist many most interesting early Celtic monuments, there is to be found one old stone which is possessed of this singularity: that on it there is engraved the only inscription in the ordinary character of the Celtic manuscript which is to be found in Scotland outside the bounds of Iona. That inscription has been thus read by the late Sir James Simpson: "The stone of Drost, son of Voret, of the race of Fergus". There is considerable probability that the Drost here commemorated is the Drost son of Ferat and king of the Picts referred to above [i.e., Drest son of Uurad].[3]