The method according to claim 34, wherein the first cationic polyamine component has an endosome membrane disruption promoting component of the formula ???B???(R4)R, wherein R is a absent and B is a bridging group of the formula: ???(CR1R2)j=???X???, in which R, R1 and R2 are each hydrogen; j= is 5; and X is N(R) and where R4 is a type (iii) cholesteryl derivative of formula (3): R6a is O???C(???O