A friend of mine, teacher at a primary school in Komotini (Thrace) Greece, just sent me this siren photo. The siren looks quite small and sits on top of the school. The photo isn't very clear, but it looks nothing like a european siren. Could it be a Federal or Darley model x?
http://3dim-komot.rod.sch.gr/ (the school and the siren for size comparison)