ok, lets get the low down about reprogramming second hand keys..does it work or not, there are many on ebay to be had...
1st thing, of course you will need a new blade cut, this can be done easily..

2nd, on older keys that have a separate transponder chip like the 02 to 05 keys these can only be programmed once and as yet i haven't found any one that can supply them as they are rolling codes,

3rd the blip part, there are several ways of programming them I.e ignition on/off hold button down ect ect. do any of these work, if so please let me know

reason why...my key went through the wash, still works but the batt goes flat with in a few days
must be shorting out in side under the battery plastic and i will have to unsolder it and try to repair it.. but i wanted to try to program a second-hand key to open and lock just encase this went wrong
.
i can get a new key from the dealers but they want you to pay up front, and you have the option of ordering number 1,2,3,or 4 on the keys, there is no info on my keys to tell me what number i have and they cant tell me, so if i buy a number 3 key and my spare key is a number 3 key the new one will knock my old one out and it wont work,"back to one key" if your ignition has been changed then the key wont fit at all.

the best bit is you wont get your money back
any idea of what the best ting to do is... V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster

I had the same with my key, went to dealers ordered a key "2" (Thinking I had a key "1") and ended up with another key "2". Now when one is set up, it unsets the other and visa versa. Now a £130 lighter......

That was with my other Range Rover, I'm in the same boat with my newer Range Rover, what key number do I buy? This could get expensive!!!

now this works !!! as i have just done it, removed the newly programmed circuit board and put it in my original key opens,closes and starts just fine...hopefully not more battery drain.
remember this programmed the second-hand key to open and close the doors only, will not start the car

Method 2:

To do this procedure you need to have one working key and one key that
needs to be programmed.

1) Get in and close all doors.
2) Turn on the ignition and turn off quickly. (No more than 5 seconds)
to start the process. Next action must take place within 30 seconds.
3) Remove the 1st key.
4) Hold the key up near your left shoulder (this is so it is closer to
the remote receiver antenna.
5) Hold down the unlock button and press the lock button 3 times.
Release the unlock button and the doors lock which confirms the operation.
6) Quickly repeat steps 4 & 5 for key #2 etc.
If it does not work, try doing the keys in opposite order. Key 2 then
key 1, vs 1 then 2. V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster