Go to Dashboard > Custom fields > New > Select type: Address search
Show on Hourly hire: Yes
Charge for pick up: No - there will be no added charge for Base to Pick up
Charge for pick up: Yes
Charge type: Fixed/Price per mile - selection here will determine addition of flat charge or price per mile/kilometre from the Base to Pick up Address.
Charge: input field for the charge value
Don't forget to click on Save after you alter the settings here.