Id try bleeding it to make sure there isnt any air at all, if there is the slightest bit it can make a huge different,
also my clutch differs when i use different oil! I use realy thin stuff and if you use thick oil it can make it heavy or really drag! Only thing is the clutch rattle is louder with thin oil, does no harm though.
I now use dextron 3 which can be made by any oil company, its a transmition fluid for automatics, halfords own is very cheap and also its made by motul apparently,
Id try these as they take less time and cost less before you pull it apart!
Gav