Have you tried?
bmw-key-replacement.com
Might also be others worth trying if you do a search.
Also worth try checking the receiving unit.
The procedure below applies to: 2002-2006 R50 MINI Cooper and R53 Cooper S Hatchback, 2005-2008 R52 MINI Cooper and Cooper S Convertibles. This information was posted in our forum pages. Proceed at your own risk. If your key/remote wont unlock/lock
The procedure below applies to: 2002-2006 R50 MINI Cooper and R53 Cooper S Hatchback, 2005-2008 R52 MINI Cooper and Cooper S Convertibles. This information was posted in our forum pages. Proceed at your own risk. If your key/remote wont unloc


Mini Cooper 2001 to 2006 How to Fix Key Fob that Won't Lock Unlock
...
www.northamericanmotoring.com
Might also be others worth trying if you do a search.
Also worth try checking the receiving unit.