New KF build problem

[safk]

I have just finished building a KF but when I ran it up it didn't sound right and after investigation I have found that the shaft with the spur on it moves side to side about 1mm with the bearings also moving in the housing. It also wobbles a little which obviously makes the pinion spur mesh inconsistent. The shaft with the front pulley on it also has a similar amount of lateral movement. Am I missing something obvious here? Double checked the manual and it's assembled correctly.