I'm UK also. Will take 3-4 weeks for it to arrive and get through customs.. but it's trackable all the way so you'll know where its at..
Will give you time to go over the build manual and get anything you need (RTV.. (Halfords sell it btw) etc) and some vibration dampers fort he stepper motors if you want them (I use Astrosyn.. UK company). Lots of advice already on here about useful upgrades to do during the initial build that's worth considering.
I personally found it useful to tinker with an Arduino Uno board while I waited.. It gave me a base understanding of how the code works as the controller board is essentially an Arduino.. not required but it certainly helped me and allowed me to mod the UI etc to my liking and change a few settings I wanted to..
Once built is it a learning curve to print well but it's not a black art. Once again you'll get lots of help on here and plenty of historical troubleshooting solutions.
Easiest modelling CAD software is Tinkercad.. it's aimed at kids but it's really good to quickly produce simple items though complex objects are easier in full on CAD software once you've got to grips with the package. Main drawbacks of Tinkercad are it's cloud based (i.e. it's sometimes not available or very slow) and your required to allow 3rd party cookies while your using it..
The two main control packages are Repetier Host and Matercontrol... with the latter being championed by the latest manual. Seems to split the community as to which is better so my advice is to try both and see which one you like best. Personally I've found RH to be more reliable and offer better control/ user feedback but many people prefer MC as it's got some great additional features... so worth checking out both as I've said.
Good luck with the build.
but oh well it is what it is 
I had to go and collect it from the courier depot but didn't have to go far to get it. I can't do much yet until the Permatex Ultra copper RTV gets here though. So it will probably be next weekend when I get started on setting it up. 