well, because,

as Londoners know, and many others don't, Camden is a borough which is much bigger than Camden Lock and Camden Town - in size, and vastly bigger in range. Touching the City of London in one corner and Oxford Street in another, it reaches north to include Hampstead Heath up to Highgate. We're biased of course, but we think no other London borough offers the sheer variety of interest that Camden does.

   and

we're Camden qualified guides, but our knowledge and interests extend to other parts of London. We are insured to guide throughout London, some of our walks include neighbouring areas and we're starting to guide in the Borough of Brent.

      So

our Camden walks are not just about the Camden that foreign tourists have heard of, and our walks are not just in Camden!