From memory the key on a 98 Rover isn't chipped, the immobilizer chip is in the remote central locking keyfob, so if you have this all you need to do is contact a rover dealership with the chassis number off the tax book (they will probably ask you to come in with id) and ask them to give you the key code. With this you can then go to a good locksmith and get a key cut. If you have lost the keyfob too it is possible for them to be sourced through a locksmith but it would need to be programmed to your vehicle which will mean a call out charge etc etc! See hickleys.co.uk for further info. BTW not linked to them.