i did the clutch last year on my td4, i did try to do it leaving the ird inplace but realised its easier to remove it, just lack of room,
like most jobs once you have done it once its so much earier second time ,
1,support on axel stands, remove front wheels, remove the subframe , drive shafts, disconnect prop shaft
2, support the engine , i used some pull lifts, remove battery,and battery shelf, and engine support bracket, with a jack supporting it lower it down this gives you so much more room to get at the bolts around the ird amd g/b,
3, drift out the pin for the gear selector linkage, and disconnect the clutch hydraulic pipe coupling
4,unbolt ird and tie it up out of the way,( i didnt disconnect the cooling pipes)
5,unbolt the gearbox making sure it is supported, do a final check to make sure all bolts are out before trying to seperate it ,
its not a difficult job, just not a job you can rush, i did it on my own about 16 hrs i guess
john t