@fletch, @ScruffR has a great idea but there was some discussion on this in an older topic:
You may want to swtich to an analog pin (A0-A7) instead of a digital pin (D0-D7) for your control line as it seems the power-up glitch is not seen on those pins. Just in case this is confusing, the analog pins CAN be used as digital pins with the same pinMode() command. Combine that with @ScruffR’s suggestion and and see what happens.