Yaris 61 Plate Remote Key Issues

[MJG200612]

TSprint Yaris tried to reprogram the key by following internet instructions & at the end the key locks the doors but a second later they all unlock. This works a couple of times and then the key stops working. All doors lock close with the internal push button. Previously have replaced car & key Battery. This all started in March when the radio would not turn off even with the engine off and key removed. Mechanic has disconnected the radio and the car Battery no longer drains. I can only lock/unlock the car by inserting key into door lock. Any suggestions - thinking it may be the relay or the actuator but I may be completely wrong.  Thanks in advance