First time build - Steel Frame CNC Router

[examorph]

routercnc - Thanks, will go down the epoxy route on the X and EcoCast plate on the Z.

JAZZCNC - Thanks for spending the time making the changes to the model to show me, this is much appreciated!
Any chance you could send me the SW files for this please or let me know what size rad it is and I will draw it up? Also, just to confirm as I haven't done much machining so not sure, what flexibility does the spindle overhanging extra 100mm give you? Is it normal to machine stuff which sits off the end of the table?
I will get a Mig welder arranged as suggested and also have a play about with the gantry sides and see if I can setup what you've recommended, should have some images up for comment soon.