I'll try to be Brief.

immobiliser flashes normally when locked.

When the key goes in the ignition it starts flashing rapidly

When I turn to start, nothing happens other than the radio panel going dark.

Battery is fully charged

Changed the battery in the key fob

Did the self diagnositic heck and I get a single flash, 3 or 4 seconds delay, then 3 rapid flashes, this repeats.

I tried the turn to start, wait 10 seconds, turn to off, wait 10 secs try again, repeated 3 times also, but no joy

Any help much appreciated

thanks .

 

Do you have a spare key to try?