Intermittant rf key issue

[powerandtorque]

did you see the small black plastic chip inside the keyfob??    really easy to miss if you don't know its there and what it does.......really insignificant looking black plastic thing....a miniature black brick but oh so important!!

That's the transponder chip for the immobiliser and nothing to do with the RF central locking.

If the transponder chip is missing, the symptoms would be the opposite of this - the central locking would work, but you wouldn't be able to start the engine as the ECU would remain immobilised.

Best guess if the key worked fine before and now doesn't after dropping it, and you've replaced the battery, is that you've cracked a track or joint on the keyfob PCB hence the intermittent nature. 306 keys are normally pretty robust compared to some others, but they're not indestructible.