  We investigate the renormalisation group effects induced on neutrino mass and
mixing parameters in a triplet-extended minimal supersymmetric standard model
where a vector-like pair of hypercharge $\pm 1$ triplet superfields is added.
We first rederive the one-loop renormalisation group equation for the effective
neutrino mass operator and, for the case in which this operator originates
solely from the decoupling of the triplets, the corresponding equations for
neutrino masses, mixing parameters and CP-violating phases. We compare our
results with the ones obtained previously, and quantify the importance of the
RG induced corrections to neutrino observables by means of numerical examples.
In the second part of the paper, we study the correlation of the model's
predictions for the lepton flavour violating processes $\ell_i \rightarrow
\ell_j \gamma$ with the measured neutrino mass squared differences and mixing
angles. We also emphasize the r\^ole played by the unknown reactor neutrino
mixing angle $\theta_{13}$ and the Dirac CP-violating phase $\delta$. We point
out that, if $\tan\beta$ is large, the results obtained in the commonly made
approximations may deviate significantly from the ones following from solving
numerically the relevant set of renormalisation group equations and using the
exact one-loop formulae for the decay rates.
