It´s definitely a Rothschilds to the left and a Reticulated to the right and the one in the middle should be another northern subspecies, a Western (G. c. perlata) or Kordofan (G. c. antiquorum).
Benzoo and Tarsius you are right. I think the middle male Diko is from Antwerpen or Plackendael. And these three males represents all the giraffe forms in Europe...or am I wrong (zootierliste doesnt work today)?