Thank you for everyone's help here. the software I am using is GBRL Candle latest version. With regards to the first reply, I actually took the machine apart and rebuilt it to better instructions, as the ones I had received were not very clear. They also made no mention that you had to calibrate the CNC machine.

I believe I may of found an issue with the machine, while calibrating, (which I did via a video on the internet). The x and y axis's both calibrated with 798.xxx which I have updated in the GBRL software. However, the z axis seems to have the issue I think; when I measure the distance from the top to where the spindle part is, I get a measurement of 11.06 mm. I then drop the z axis using the steps like I did for x and y, say 20 mm but the distance is then only 11.06 mm so only gone down 7.35mm. When I have put 30 in the Steps field, it only goes down a distance of 12 mm. I have down these same measurements 5 times and come up with the same results.

Just out of interest, I am considering purchasing a laser for this machine. What is the 'SainSmart 445nm/5.5W Blue Laser Module Kit' like and is it worth £135?

Once again Thank You.