Ivan note that 'J' (I assume) is using E5 when he can, and using additive when it is not readily available.Millers VSPe has worked well for me when I've been unable to get super unleaded.
Its more for use if you plan on laying up the car for a few months. Stab-bil reduces the chances of the ethanol creating gunk and absorbing moisture.What type of e10 fuel additive would you get in the UK for my p6 rover
Thanks