Well, this would have been fun to have found prior to I Do, I Do, I Do, but here it is nevertheless.  It's both a nice set of quick examples of British regional accents, and a testament to the skill of the dialect coach who is giving the demo.
Many of us, but especially American student performers, occasionally need a reminder that other countries have regional dialects and accents just like we do.  When developing your character for performance, it's important to consider the region in which they live, and the social context that surrounds that region.

Just like an American southern accent delivers both location and social information about a character to the audience, the same can be said with regional accents from other countries.  It is a little more challenging to develop a foreign (to us) characterization to that degree of specificity, but thanks to the internet, we have a much wider pool of information available to us.

Beside Youtube videos, I strongly suggest the International Dialects of English Archive, which contains a searchable database of English spoken around the world:  sorted by country, region, gender, and age.
I have been experimenting with MOOCs; that is, Massively Open Online Courses.  These are online classes that you can take, often for free, hosted online by institutions of some prestige from all over the world.  There are several MOOC hosts out there, but the one that I am currently using is coursera.org

For my first class, I chose Introduction to Music Production, presented by Berklee College of Music.
As part of that course, I had to create a five minute video explaining the difference between microphone types found in the common home or small studio.  Below, is the video: