Preferred method for internal links is node id followed by link label:
26 => 'Why BHS Matters'

Urls are also ok.

For internal urls, domain name is not necessary:
'shows_events' => 'Shows and Events'

For external urls, http or https is required:
'http://www.bhs.org.uk/' => 'British Horse Society'

- node id is preferred so as not to lose reference if the url is changed
- if using local url: do not use initial or trailing slashes:
	OK: 'shows_events'
	NOT OK: '/shows_events/'