For the £2k, you're getting ball screws (the standard machine will only have acme lead screws), and lots of extra bits that allow motors to be fitted, along with a controller and some form of software.
Most ready to run CNC mills of this size are pretty expensive, as they're not produced in the same quantities as the manual machines, and there are increased support costs.

Personally, as you say electrical boxes, I'm assuming plastic/die cast enclosures?
In which case I'd look at router style machines, as they'll be far more suited, provided they have enough room under the spindle.

Software to run machines varies from free to expensive, but it all depends on what controller the machine uses. LinuxCNC is open source, and reasonable good. Windows has lots more options. Mach 3 or 4 is one of the more universal options, but there are lots more that are specific to certain machine controllers.

However you also need to factor in software to generate the required G-code that the machine software accepts, which can range from free to extremely expensive, depending on what you'd like to do.