Glad i could be of some help. Though, going back and reading some of the things i remember, it appears i got most of that info from on this forum, your post in fact lol And the other forum members explain a lot better than i do. I've been on multiple forums these past few days reading up on mobile broadband and everything melds into one, plus it was very late in the evening
I do hope you get your issue sorted. I've had nat trouble in the past with another ADSL provider. Most of the time it can be sorted at your end, other times it's better just to switch provider and be done with it. But i don't think you're going to get anywhere with EE, not without technical intervention on your side.
Michael