Ok so i lost access to my boards altogether so reverted the init.php script to the one that came with vb3.5.7 rather than the one I'd changed to add in
require_once(CWD . '/includes/functions_gallery_store.php');
and all of a sudden the gallery install script works with a single error line along the top of the first page but after that everything seems ok.
this just happened so i dont know if it was a complete success yet.