Thanks again for all the advice.
On reflection, the BP test does not stand up to scrutiny, and was very poorly designed. A 'between groups' test on just two high performance cars, with minimal, limited and vague reporting of variables is not enough to justify their claims. The TMS report is however far more convincing.
BHM advised that the ECU will now detect, and respond accordingly to a change to a higher octane - but I was hoping that the 'premium' fuels have other ingredients as well that will have an affect.
Any re-mapping will have to wait until warranty expires, hence my interest in a quicker 'uplift'.
Think I'll try a switch to Tesco 99 however, out of interest, and see if I notice any difference.
