Paul , what mounting plate does your scope have ? as I have the old one off my C9.25 after fitting a FT .
It's plate is 79mm x 53mm with 4 x 1/4 inch holes at 38mm x 72mm .
The focus knob its self fits in a hole 24mm in dia that's off centre by 5mm on the 79mm length and 20mm to the centre from the side that's 53mm .
Let me know if yours is the same as there are 2 styles and if yours is the same as mine you can have it for postage .
Brian.