This website identifies the location of the town of Dasbyio (with that additional i in the spelling)
as here. So pretty close to your marker Els.
There are some roundish looking things on the satelite images, though
this picture shows them to be shurbs. It is hard to pick out anything really matching the description:
The size of the mounds is 2 to 3 m high and around thirty meters wide. They are made of black stones.
Like you Els, I can't initially pick out something in Randa that matches the description either.
Though from looking at
christravelblog's photo they may not be especially easy to pick out (nor likely to be inscribed).
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Just discovered an alternative spelling in French:
aowelosLed me to
this french wikipedia page and
this article in le Monde, the google image searches look much richer for this spelling, with
some research papers with maps, the site on the maps identified as Asgoumhati doesn't seem to be too far from Randa, could be promising.
Have to get on with some work but it could prove more fruitful.