Can i get a new thermostat control knob assembly for Moffat Module 90 oven?

The Moffat Module 90 is a gas oven and grill. It was bought around 1990. The thermostat control knob assembly is faulty and the spindle is very loose. It works if you hold the knob in certain way!
Is it possible to get a new spare part? Spare part no. in Fitters Instructions pamplet is D0075B0 (white). ) G.C. part no is 010527.
Apart from this all other parts are fine, the oven has not been used that often.