Firstly, the Nutrocker has are fans around the bottom of the hull- it is a hover tank after all. After some rummaging around the local hardware shops, I found some special washers which looked like a good choice for use as fans. I used two small washers side-by side on each corner of the hull, as opposed to one big one on each corner. For the nubs in the middles I used little bits of trimmed off sprue.
The Nutrocker also has a bulge on one side, presumably for a radar or some such. I used another key finder back and greenstuff to model on this bulge (although I think it's on the wrong side if this were a true Nutrocker build).
I added another bump by using a Tau shield generator and more greenstuff. For inspection panels, on the hull and around the fans I used card in 5mm strips, stuck on with superglue (I was too impatient to use PVA glue). The cards a bit thick really, and some of the lines are far from straight, so plenty of room for improvement next time.
At the back I used a Tau antennae array and made an inspection hatch and on the other side from the bulge I did some more rungs using staples & greenstuff.
That's it for now. I should hopefully be doing the polyfilla work on Monday.