Don't tow in O/D but you def have issues other than that.
Is the fan shroud in good nick and did you check the fan blades for cracks at the base of the hub?
Was the Rad simply flushed or was the Rad removed and the Rad core rodded? Flushing does bugger all and the thermo camera won't tell the full story unless under load.
Block the EGR if you haven't already done so.
An external tranny cooler will help as well.
Buy a Scangauge or equivalent, absolutely the best bit of kit for any CRD engine... it will tell you the boost and the also the coolant temp and a myriad of other things.