Generally, GUV permeabilisation occurs near-simultaneously or with a lag time compared to GUV growth from the fusion of MO lipids into the bilayer structure. We attribute the influx of large macromolecules such as 10 kDa dextran into the lumen of the GUVs to be induced by the formations of pores in the vesicle membrane. This is likely due to the enhanced curvature elastic stress in the GUV membranes due to the non-bilayer preferring MO lipids, which favour highly curved structures such as toroidal pores. The stochastic resistance to leakage by some GUVs in the sample is suggestive that the enhancement of membrane permeability might be suppressed under appropriate conditions, such as different GUV membrane compositions. After the GUVs were observed to swell during a growth process induced by MO incorporation, a stability limit appeared to be reached, beyond which a rich array of morphological transitions was observed in the GUVs.