It says in most cars handbooks that they should be run on 98 ron, and have to be adjusted to run on any less, but most right hand drive cars have this setup when leaving the factory so run on 95ron ok.
Like Kevin says, if you intend to run a higher octane, its advisable to get the timing advanced to suit.
I'm not sure if using a higher octane would actually ive any benefits looking at the facts, but I hope someone can tell me otherwise!