Hi Paul - I moved this topic into Repatriation, and hopefully you can get some insight here. Lola is right about the DCF - it isn't really the process for you guys. It is for couples who area already living in England and have properl established residency here - meaning they've actually lived in the UK with intention to stay in the UK.
For clarification, let me see if I understand your situaion... you and your wife are both Irish nationals, right? Both of your jobs moved you to the US - and she gained US citizenship through living in the US long enough with her work visa. You however had to come back to the UK, and have just been visiting her there. Now you want to move to the US. Do I have all of that right?
If so - I am guessing the way to get you to the US is through her filing a spousal visa - in the US - for you. I've never done this, and so it is just an initial guess - I'm sure other people can chime in here with some more concrete info... I do know, though, that the DCF isn't designed for your circumstances.
Hope this helps even alittle bit! I know it is all very confusing at times...