As I'm building the OX I thought I'd stay true to Mark''s video tutorial as much as possible and went with the GRBL and the Arduino Uno. All was well with the setting up and connecting the power, everything lit up and I was able to add snippets of code into the Arduino interface and get the Nema's 17 and 23s to spin happily. Its quite something to see your handy work come alive and do what its supposed to do for a change. As I say, all went well until I set up the Universal Gcode sender. I tweaked it as directed by John from NYC CNC who's video got me this far. Anyway the Gcode Sender wouldn't work and I don't know why. Perhaps someone would have a look at the attachment and suggest a salution. Thanks.