I have just checked our G code and it is reading G17. I have changed it to G21 it made no difference so i thought i would try G20 as well just to see what would happen it just ploughed straight down into the board so i quickly cancelled it as i didn't want the machine to get damaged.
I am starting to think that maybe there is a dodgey connection some where as i am unsure as to why this is happening. We have had the pendant apart to check everything is in tact in there and all is fine.
Thank you for your advice!