For a daily driver car which occasionally should be used on track i really see no other option than running with a arb.
Reason is you can go with softer springs/dampers as the opposite dampers will help against bodyroll in a turn.
Also when you can run softer dampers/springs you will suppress the bumps in the road better.
I dont know how it is in the uk, but the tracks in norway are quite bumpy which means that a full on race setting with no arb (meaning really tuff spring/damper ratios) will prolly throw you off the track.
Maybe for a really experienced driver no arb is the trick, but i really dont think so.

For gravel use you can do without the rollbar as you really want independtent suspension to give more traction/grip on the bumpy surface.