Had to rectify the same gear sticking problem with mine as well. Was having a hard time getting gears and when I did had very little pull.
As Tony said above, my problem was with the release bearing hitting a very small ‘burr’ on the drive shaft. Once this was knocked off I was left with a new problem that I couldn’t get 4th gear. I fixed that, once I turned the gear stick round 180 degrees facing the right way!
Lucky I took before and after pictures of everything. You can see what I mean about the gear lever in the two pictures
Mick