Yep, AN-12s at BHX is not that unusual. They used to be regulars at my local airport, Maastricht, until they and Antonov 24/26s, were banned because of noise complaints by a few local residents, all of which moved in close to an active airport and then started complaining about aircraft noise!!! This included an Air Traffic Controller who worked at the airport, bought a house right next to the runway, and as soon as he retired joined a campaign against aircraft noise!!! Bear in mind that movements at Maastricht are quite limited in numbers anyway.