The application still worked - could see that with the serial monitor! However my IDE now gets a failure on avrdude when I try to upload a new sketch. Think I need to restart my PC because restaring the IDE did not solve it. I'll be back
That's because you likely blew away your bootloader uploading the binary - so you'll need to find a bootloader binary for your board, and upload that again so you can upload sketches with the Arduino IDE (if I am understanding you correctly?)...