Thank you for the pointers, I had wondered if my gantry was making life difficult, I was trying support the weight rather than hang it however I suspect I was trying to run before I could walk… The Z axis is the bit that I have found hardest to get my head around, I did indeed mean 5mm steel plate, your tooling plate suggestion seems like a much better solution, I will look at the Z completely afresh. Good to know that I am not too far off with the electronics, the idea of a belt driven 1610 to give me different gear ratios makes a lot of sense.

I really appreciate the help, building from scratch is a pretty daunting process but I do enjoy a challenge!