Hi Ron
Last week i got a new board designed with all the recommendations and tested it by simulating all the conditions and it worked fine.
I then checked the current sink,and it still was oscillating.I tried a lot but could get the oscillations removed.So i replaced the MOSFET by a TIP122 and adjusting biasing resistors.Still no go.
So i removed the Load from the high side and put it below the Transistor (just above the sense resistors) and juggling a bit,i got it working eventually!!!!
Now perfect replication of Current-set --> Load --> VDIFF -->Dac-ref-set-->VCAL-->Vsample
I am very happy
Thanks and regards