The TEMPO/PROGRAM Wheel device Circuit reference is SW1101 and its Part Number is QSRGT003AA. It is referred to as the 'Encoder Switch'

This device may be supplied complete with its own seperate small Printed Circuit board, on which it is mounted. PCB14 Part Number SXPG239011B It is referred to as the ROT PCB

It is in Greenhill's Parts list : http://www.wdgreenhill.com/manu/technics/technics_parts.htm
Probably best to email the company......