Never the twian shall meet.!! . . . . That is wood and Mills. . .Lol

If you have a Mill then my suggestion is keep it just for work that requires slower speeds and feeds. Both Aluminium and wood require much higher feeds and spindle speeds to get the best from them. Mill with only 3000-5000rpm and high pitch screws will struggle badly with wood and be slow when cutting Ali.

So really with only a Grand then it's a no brainer you have to DIY. The Chinese machines are ok for learning on but if you want to earn some money with it and be pushing then they will let you down quickly.

Then with only a Grand you won't have any room for error or wrong buying if you take the DIY route. So consider this choice carefully has well.
My best advise is if DIY route then save a little More.? Another £500 will see you with a much better machine.

The fixed gantry setup at this size is good choice but it will take more room than moving gantry giving same cutting area so bare this in mind.

If you do take the DIY route and time isn't a pressure then Throw up a Thread and We'll help you with design and buying the right stuff from the right places.

Me personally I will offer now to help you with both Design/Electrics and cutting any parts if you take the DIY option.

Good luck and tread careful because a Grand isn't alot and can be wasted quickly when it comes to making wrong choices with CNC.!