If you go here;
http://blogs.balupton.com/index.php?blog=5&p=210&more=1&c=1&tb=1&pb=1

And look for;
Display Mode: Basic, Enhanced.

The link for Enhanced is:
index.php?blog=1&cat=85&page=1&gallery_display_mode=enhanced

Instead of
index.php?blog=5&p=210&more=1&c=1&tb=1&pb=1&gallery_display_mode=enhanced

(Note i've removed the domain from the above to stop the url from being shortened in the forum)

I'm using the following

href="'.regenerate_url('','gallery_'.$c['name'].'='.to_string($cc['value'])).'"

This is driving me bonkas.