Would like to know your method, i have had these fork tops off quite a few times now, mainly to change the oil. My method is to soak in wd40 overnight then screw a 12mm fine pitch bolt into the slug, slip a flat bladed screwdriver in and pop the circip out. Mole grips on the 12mm bolt if needed to wiggle the slug out, do this when forks still in yoke and same when assembly. Red rubber grease on the seal and pack before putting the plastic cap back on keeps the worst of the weather out. My fork seals are the originals also the springs, still in spec. When it was new a 20mm spacer was used to preload the front a bit more and 5W oil was perfect for the damping. On the road had fork gaiters most of the time. Have done a few where you have to take fork leg out and use the fork spring to punch the slug out. Cloth over hole obviously. Rob Ok , I don't have any threaded holes in mine . Anyway , all I do is keep the handle bars on to use as a fulcrum and get the biggest Allen key in my toolbox with the short end on the slug . Pull up on the long end to push against the spring and pop the circlip out with your free hand . Then the plugs should slide out easily. Sounds like yours at a bit reluctant.