Studies of the interaction of 2 MeV He+ ions, employed for Rutherford backscattering/channeiling of disorder in InP, with the disorder generated by pre-implantation of 40 keV N+ ions at room temperature are reported. It is shown that for initially undamaged substrates, He+ irradiation generates disorder whilst for N+ implantation damaged substrates He+ irradiation anneals disorder. Possible mechanisms to account for this behaviour are discussed and the potential problem associated with accurate disorder measurements using RBS/channelling outlined.