Image in Flexible Content .. can't get ID

[codemonkeynorth]

Hi,

I've got an image within a flexible content block and I'm trying to get its ID so I can pass it to a WP function

$blocks  = $post->acf->flexibleContent('flexible_content_blocks');
foreach($blocks as $block) {
  $image = $block->fields->image;
  $ID = $image->ID; // fails
  wp_get_attachment_image($ID,  'fullsize', '', ['class' => 'foo']);
}

currently using

"jgrossi/corcel": "2.8",
"corcel/acf": "^1.1.1"

(I can't update due to other dependencies currently)

thanks for any advice