Thanks John, I replaced your response into the query but still not getting a URL (or anything returned) still – did I got the below right?
<?php $image_file = get_sub_field( 'image_file' ); ?>
<?php $image = wp_get_attachment_image_src( $image_file, $size );?>
<?php $url = $image[0]; ?>
<?php $size = 'overview'; ?>
<?php if ( $image_file ) : ?>
<?php wp_get_attachment_image_src( $image_file, $size = 'overview', $icon = false );?>
<?php endif; ?>
