Well, I don't have time to go into gory detail, so I suggest reading the book
URL below. If you prefer a single HTML page so you don't have to click through
lots of individual pages, this URL will also jump you to that chapter:
http://svnbook.red-bean.com/en/1.5/svn-book.html#svn.branchm
Thanks for the post Quinn, I am however completely lost!
I have a Branch 'sandbox' which is sitting at revision 251 and the
trunk (which has has a couple of changes since checkout of sandbox) is
247, any help on this would be great, did manage to run a diff via
terminal, but still completely lost.