I think i have found the problem.
I removed the SD card so that i could update the firmware however my PC couldn't sustain a connection for more than a minute or so. I was able to copy the firmware off the SD card and load it onto a new one, then followed the steps on https://duet3d.dozuki.com/Wiki/Installing_and_Updating_Firmware#Section_Fallback_procedure_Num_1, and so far it is working. So a bit strange but it looks like it was the SD card + firmware needing updating.