well i finally have a clutch, but i'm certainly not convinced that there is not still air in there. I collected dome of the fluid in a jar and even though about three quarters of a litre have now gone through, the stuff in the jar is dirty. Left to stand it clears and black dust/grit collects at the bottom of the jar. SO..i reckon either the masterclylinder seals are going too, or more likely the flexi hose coming up to the slave is deteriorating internally. Somebody else here said they fitted a new slave and it went again in six months or something. This could be the explanation, the flexi hose breaking up in depositing grit in the slave cylinder, which in turn abrades the seal during action and finallly causes it's failure. I'm going to replace the hose and see if the fluid comes through clear.....ah joy...more bleeding....more 'I'm not doing your bloody ironing as well as this' conversations!!!!