Trakehner x T.B. I have just bought 17.2hh Gelding 6 years old very green?

Does anyone know about this breed of horse? I have just bought a youngster who has done nothing due to lack of time and experience of owner. He is also very immature in his nature and in his body, very leggy, is this a normal trait? He is extremely loving on ground and easy to handle but apparently naps out hacking. Please can you give me any info about this type of horse.