Changed the Strut by the roadside and gained my suspension back. So was able to drive the patient home. 
Seems also that what I suspected was height corrector linkage sticking was indicative of the impending failure of this strut so had I known the warning signs, then perhaps action before could have averted this. Obviously most of the front suspension thrust was being provided on the drivers side. Instead not realising, I was lubing and greasing the linkage of a suspected sticking HC to try to get it to rise faster in normal because it seemed OK in intermediate.
Hey,Ho we live & learn!
