When I bought my X-Type it, like many used motors, only came with one key.
Not wanting to risk only having one key and not wanting to pay dealer prices I have now successfully programmed my own
I bought a second hand key fob with blade from ebay for £25 (the remote functions can be programmed using key on/off/on/off etc that can be found elsewhere in these forums)
Next, I bought a precut blade on ebay for £10, they cut the key based on a couple of photo's of I sent them of my current key blade. I also used a friends ebay account to buy this so it was delivered to their address and not mine. Maybe I am a bit paranoid about security
I then replaced the blade in the keyfob with the new one.
At this point I could unlock/lock doors with remote and turn ignition on with the new key but not start the car.
With JLR SDD running and the VIN detected a new session was started.
In 'Service functions' there are two transponder options.
Add additional transponder (requires 2 working keys)
Program new transponder (requires 2 keys that one or both need programming)
Selecting 'Program new transponder' and accepting the warning that it is all my fault if it goes wrong the next steps were pretty simple.
First SDD asks you to delete all existing transponders (pretty nerve wrecking) so I clicked OK
After a couple of seconds SDD asks to insert first key into 'off' position, done & clicked OK
Turn ignition on, done and clicked OK. There is then a short message whilst it writes data to the security module.
These steps are then repeated for key 2
Job done, I now have a second fully working key for a total cost of £35