If the steering is tensioned against the lock pawl, then the retract motor can't always pull the pawl clear. In this instance just turn the wheel a bit to allow the lock pawl to be free of tension. If this doesn't work, then check all the electrical connections to the CJB under the glove box. Sometimes passenger's can touch the wires, potentially causing connection issues.
Also as above, if the battery is over 4 years old, it is best to simply replace it. The Freelander 2 is very heavy on batteries, often causing them to fail suddenly without warning.
Also when starting the vehicle, it's best to allow the system check to complete before pressing the clutch/brake, as a less than perfect battery will cause all sorts of communication errors on various modules in the vehicle.