I finally got round to stripping my forks last night and thought I'd update this old post as it may help future / current 620 Sport owners, knowledge is power an all that ...
I took the springs out of my bent forks last night to confirm what they were and be ready to fit them to the new forks, and now know they are not standard. These springs are single rate with a wire thickness of 5.0mm and ~285mm long. This compares with the standard springs that came in the bikes spares box of being progressively wound and only 4.7mm OD wire thickness and 290mm long.
And although the front end maybe a little soft, it feels pretty good, I just need to avoid hitting stationary bikes in future
