Riley Car - 'R' Gear Stick Knob

This is a gear stick knob with the 'R' logo, designed for Riley cars.
There are 2 files for 2 different gear stick thread diameters, 9.5mm is for Riley and some classic cars, and the 12mm is for modern cars.
If you find the thread slightly tight thensimply increase X and Y size by say 5% and then retry.
Please let me know how you go and what car you use it for.
Photos would be great