After searching and looking through a lot of threads on here, I thought I would sum it all up and do a flip key step by step guide for the Leon. One of the first things I will say is that (for me anyway) I paid no attention to the frequencys on the key. Just making sure that I brought a Hella version. My leon Key is as you can see a 433 Mhz key and he one I brought from ebay was a 434 Mhz key and works the same I brought the replacement key from ebay from autopartcentre the item I brought had this in the title VW VOLKSWAGEN GOLF MK4 BORA REMOTE FLIP KEY FOB as the link will expire As he states it comes with a blank keyblade. Reprogram new remote. Hopefully you will have 2 keys - both with transponders in. I used 2 keys to do this. 1. Switch Ignition ON and leave keyONE in the ignition. 2. Mechanically lock the vehicle using the Drivers door using keyTWO 3. Using the remote control(flip key) press the UNLOCK button once, and the horn will sound once. (mine didnt) 4. Wait 6 seconds and press the UNLOCK button again to activate the coding procedure and the horn will sound once. The remote control will now be programmed. Happy days Now the blade swap Prize apart old (remote in my case) key and remove transponder, little glass tube. DO NOT LOSE as this is whats needed for the door/ignition in the new key. The transponder in mine was lose, some maybe glued in, Meths/Nail varnish remover will soften this glue. Prize open the flip key with a large flat bladed screwdriver here The Blade of the flip key needs to be removed undoing the screw which has sneakily been hidden under a VW/Skoda badge. Badge can be prized out with a smallish flat blade screw driver. No need to worry about the old badge ehhh With the screw CAREFULLY removed, inside will reveal all. The silver button which you press, spring to create the flip and the blade itself and of course a old transponder. Throw away this as it is of no real use. Insert your old transponder from seat key. No need to glue as its held in place from the other side of the key. Get the blank blade cut. I know that Timpsons do this and these are pretty much everywhere. The new blank blade doesn't come attached to its swivel, so get Timpsons to knock out the pin of the old blade, and put your new cut blade onto the silver hinge piece. Line up the 3 locators. It should only go in one way. Insert the spring so the bit that sticks out from the spring is at the top. Twist spring, so it engages inside the button. You have to reload the spring so that it flips open. To do this insert other side of key from above, onto the key hinge. The rotate, counter clockwise once. Hold together and rescrew the key back together. Popping the other end with remote and key loop back onto your new key. Get on the web (fleabay) and search for a Leon flip key badge or something. There we go job done. Remember the frequesncy (for me) was irrelevant Hope this helps someone.