have removed the retaining collar.spring and shims but i am unable to remove the clutch operating sleeve,[top hat] have also removed the clutch operating pin as well
I don't understand where you're seeing 'shims'. There ain't any on my clutch and none shown in the manual either.
From what I can see once the spring retainer nut and spring are out of the way the 'top hat' should just slide off the splined part of the shaft.....OZ.
ETA: Just thinking for a minute here.If you clutch has suddenly stopped driving and you can't easily withdraw the 'top hat' from the splines then I would suspect the inner spline in the 'top hat' or the inner spline on the top hat inner adjustable nut would seem to perhaps be seized/frozen on the shaft spline.
This scenario would prevent the top hat from being able to slide on the splines,hence unable to clench the plates and drive,or indeed be easily pulled off the shaft spline.
Are we getting close to the problem yet? Can you move the 'top hat' back & forth on the shaft by any amount at all?