Looks great
@fatboyroy
Some interesting design decisions on that machine. Mobile Z-Axis in particular. I get it gives a smaller overall footprint compared to work area, but stiffness suffers a good bit from that.
Highly suggest you start with wood or plastic. Crashes hurt less when the workpiece is softer material
Also, I highly suggest you write a REALLY basic program to start and test that all you axes are aligned between the virtual and physical systems. Something like move in a square and a circle in mid air, with the spindle turning on and off. Start by writing this in GCode in notepad by hand as a text file, then use your 3D modelling system to create the same code. This will give you a really good understanding of what the code does and how it relates to the machine.
Also, as you troubleshoot, remember change on thing at a time and watch the outcome. The better you isolate your tests the faster you can isolate the problem/misunderstanding.
Finally........setup some level of Emergency Stop. Even if that is just a power strip with an off button in easy reach. If the thing starts going haywire, or starting tearing itself up, don't panic, just kill the power. Take a breath, and recover from there...... seriously an EStop on a CNC is as important as a kill switch on a boat. It keeps a bad situation from getting worse.