http://www.obediencestar.com/uk.php
gives a few of the rules, but not the fine points
A few of the differences are:
the heeling style is called laid on, considered wrapping here
hand position in fronts is in front of the handler, like a target, ours must be 'relaxed and in a natural position at the sides'
there is no jumping in UK ob, however I believe they added a jump in the international class
the judge supplies the scent articles
Obedience trials are much better attended and more numerous there than here, it's a popular pastime for dog owners, and Crufts is the largest dog show in the world.
Not sure if that link will work or not, one person reported you had to join Eukanuba's 'breeder's club' or some such to view it.
George Bailey