I have a Mild Home counties accent, perhaps with a tiny smidge of Norfolk (its getting better, almost cured
)
I've never had any issue with people in the UK understanding me. Over here in the States I'm usually understood. Although I'm working for one of the largest insurance firms their main rival has a huge ad campaign starting a little geiko lizard who has an estuary accent. It causes pelnty of comments and jokes at my expense. Look up the Geico Lizard on you tube.
I used to have exactly that accent at school but mine progressed a bit (radio 4, and due to the lack of BBC I have found my vocabulary is starting to shrink. They talk funny over here)
Starting to pick up on the nuances of the diferent dialects. I used to love watching This old House on telly. They all just sounded American to me. Now I was supprised how different the accents sound when watching an episode this week.
The missus mentioned when we used to chat on line years ago, how shes mistaken for being Spanish. First time we Skype'd I just thought "Oh my you sound so American" Now I can hear the hispanic before the American. Although I'm so used to her voice I usually unaware of accent. And she's the same with me.