[AcidLotus]

If your octane is higher in the UK than what is available in the US, you're likely not experiencing any detonation. You can also rotate your distributor to advance or retard the timing - just mark it with a sharpie before you rotate it so that you know where the stock setting is. I didn't have the JR BTC to use so can't comment on how to set that. Perhaps a call to Jackson Racing could help if you have specific questions related to the device.

This guy has a pretty good write-up on ignition timing: What does "retard the timing?" mean? - Other Honda Civic Parts and Products - Honda Civic Forum