I have seen lots of posts about key re-programming, but my case is a little different.
I have not seen my specific case here before, though I'll happily be corrected:

1) Bought a 99 Disco II 3 years ago. The key in the ignition (assuming it was the original key and ignition) was getting a little argumentative. Eventually I would not pull the key out for fear of not being able to re-insert/start.
2) On Fleabay, we bought a matched set of used ignition lock and door handle.
3) Had an independent mechanic (LR specialist) install the ignition lock,
and door handle and program the key.
All worked great for 3 years until....
4) Daughter lost the one and only remote key a couple of weeks ago. This leaves us with one working, non-remote copy. Doors unlock, engine starts, no issue.

I want to get at least one remote key....
I have no bar codes, if that matters.

What's next?
Since the ignition lock is not original to the car, how can I get a new key?

Options:
A) Go to dealer buy key and have them reprogram. Can they even do that if I changed the ignition lock?

B) If I buy one on ebay to mitigate cost, and then bring to the dealer to program, assuming they will do this, what frequency fob should I purchase?
Assuming NJ LR dealers = cost prohibitive! Can they even do this?

C) I have the original key and remote that no longer fit the replaced locks...
if I get a new key insert for the fob, can the fob be re-programmed to work?
Is Remote Key LTD UK, an option?

Perhaps the first question to be answered is, does the fact that the cylinder is not original prevent a key from being programmed. I would guess not if the BCU is what matters.

Any advice appreciated. I just want to have a remote key again.

 

The key, door lock and ignition switch are separate from the keyless entry system. The keyless entry "fob" communicates with the keyless entry ECU to run the actuator motors. In other words the fact that your lock cylinders aren't original is irrelevant.

 

RemoteKey in the UK is the quickest and cheapest way to go. They send you a new key and a programmer unit. You plug in the unit and in 10 seconds you're ready to go. Then you mail back the programmer and they give a partial refund. I have been very happy with mine.
The only possible downside I see is that they are not OEM Rover keys, so a dealership won't be able to do anything with them.

 

RemoteKey looks interesting, but they say they only ship to UK and Ireland. Do they or some other similar do USA?

 

Their site directs you to http://www.remotekey.eu for outside of UK/Ireland but that seems to be down right now. They are very responsive to email though, so I would try that to see what options are available.

 

Just in case anyone else is interested, I did email them and heard back. They do ship to the US. Here is what they said...

 

Yep, they asked me for my VIN as well, and somehow were able to confirm the frequency from that.
Thought I would mention that the key shank itself is very high quality. I had other keys cut from regular stock at a local locksmith and they bent very easily; this one is solid and looks like it will hold up really well.