MK1 Freelander lost keys

Hi 2005 registration

On a 2005 the remote fob just does the central locking and alarm.
The immobiliser is a completely different system consisting of a chip in the key that communicates with a Sawdoc immobiliser ECU via the coil on the ignition barrel.
You can buy a replacement key with a chip already programmed from a LR main dealer parts department and it probably isn't as expensive as you think.
As far as I know, the key/chip will "just work" without needing the service department to get involved.