ah ha sorted it. my valet alarm code is the 4 digits in the middle of the searial number on the certificate.
can now access valet mode at last. woooohoooo 
I have concept g4 and on mine If you press the lock/unlock button and the button diagonally opposite (on the 4 button fob) at the same time, the proximatey sensor is disabled (indicators should flash 4 times to tell you it's disabled). And it will be enabled next time you unlock/lock it.
Might be worth a try on yours.