As I recall stock compression is somewhere around 10.5, which isn't as high as it could be; but this depends on the cam durations too. The longer the duration (of open) the more compression - usually.
US & European Octane ratings are measured differently (I think it's detailed on Wikkipedia, etc. if interested), so the US rating show as lower than European, but the gap in resistance to pre-ignition isn't as much as most people think.
As an example I see Turbocharged performance cars that are meant to run in Japan on 100 RON & owned by US Military on bases here, be filled up with US 91 RON and they run just fine too.
But yeah, I still put in 100RON Japanese premium fuel in my bike all the time. It's about 6% more expensive but what the hell! The VFR & my other bikes run 95 RON regular. I believe the UK is 99-97 RON premium (Depends on where you buy from) and 95 RON regular.
Euro RC51 SP2: HRC WSB Ti Hi-Level, T1 Airbox & Snorkel, PCIII, Dymag CA5 Carbon Wheels, Ti64 Spindles (F, R & Swing Arm), Mori Link, Maxton GP7 Shock & Ohlins 832 Forks, Brembo GP Calipers & SBK narrow track (F), Braketech Disc (R), Brembo billet Underslung x 2 Brembo RCS, Tyga Triple, 7075 Stem, Probolt Titanium all over, Babyface rearsets, MR Complete Carbon Lineup, Custom Undertail & CBR 1000 LED, Watsen LED Indicators, Harris Brace, Giles clip-ons, Corbin seat, etc. 2013 BOTY.