Great advice from Phil.
I can add: make sure the servo saver is screwed to the max, it helps a lot for steering. Schum stagger ribs (with no foam inside) can make a car easier to handle than front minipins, giving more consistent lap times. You can also cut 1-3 outermost rows of pins on the front.
From what I see from googling Caldicot track, it's not 100% carpet. If there are several turns on hard slippy floor you can try using worn out minipins.
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