This code
<?php if (is_single() || is_page() ) : if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
<meta name="description" content="<?php the_excerpt_rss(); ?>" />
<?php endwhile; endif; elseif(is_home()) : ?>
<meta name="description" content="<?php bloginfo('description'); ?>" />
<?php endif; ?>
added in the header works a charm. The trick is to make sure that the_post() references are only used in if statements where the value exists only for the life of the statement (When used it the header). Pages start to vanish otherwise… not forever, the_content() etc references just stop returning anything. I played with removing the the_post() ref from the body of my pages (to avoid the issue above) but all that did was result in a description always equating to the latest post as opposed to the page you are trying to make unique.
