Wow... this is incredible, you guys are absolutely amazing, thank you so much for taking the time to help me out, I didn't expect anything like this.
My problem is definitely solved... and in multiple different ways :)

@bemfarmer - thanks so much for the file, my brain would have fallen out of my head if I just saw that geometry and had to figure out how to make it. Tested it now, will definitely be exploring more of blend, seems like an incredible tool. Thank you!
@Michael Gibson - Thanks very much Michael, I get it now, reading the help file also makes more sense after seeing these, I see what I've not understood when reading about the fillet command. Thank you so much, I will definitely be considering the angle surfaces meet at now and most likely be considering a blend for this. Thank you!
@BurrMan - Thank you man, that's really awesome of you to take the time, I see your point about the order in which you fillet, I really was not considering that and thank you for the blend demo, I think that's what I'll be going for :) Could I please ask what the first application was that you were using? I couldn't see its name on the video.

Thanks again guys, I'm off to do some modeling now and hopefully end up with more than a square and circle after another 4 hours of trial and error :)
Will post some results... good or bad ;)