These pictures were taken before i took the bike apart.
Looking at them i have noticed that the distance between the Girder spring and the frame looks incorrect.The fork doesnt seem to be 'sitting' right for lack of a better word...
Are you sure it's an M20 spring?
It seems to be too long..
I just counted the No. of coils in my fork, and it's the same, but still, you can see in that your link are fully opened, (Max height) and still, the spring looks compressed, so looks like it is too long. (??)
If the spring is out and you can measure it, it should measure about 24.5cm un pressed.
I had a similar problem initially. When my bike was parked using the rear stand the spring did touch the frame but when I took it off the stand the spring seemed to fit perfectly. Plus the spring is not exactly straight but is a little bent towards the top.