How does the search clan function choose clans

I am having a devil of a time finding my old clan to rejoin. Ever time I search (the name is stupidly common but as you know you cant change it) I get roughly the same 50 clans appear. It doesn't seem to be random as the usual suspects are repeated over and over again..Any idea how the game selects the clans? Is it by recent activity etc? It's clearly not totally random.
PS - I know about the GC and invite option but dont have any of the clan on my GC friends.

Try using upper case letters if the clan had any, type it exactly the same.