Hi John
Thanks for the swift reply — I’ve tried to digest the link you provided and came up with this as the solution…
<?php $image_file = get_sub_field( 'image_file' ); ?>
<?php $size = 'overview'; ?>
<?php if ( $image_file ) : ?>
<?php wp_get_attachment_image_src( $image_file, $size = 'overview', $icon = false );?>
<?php endif; ?>
However nothing displays, altering the original string to…
<?php echo wp_get_attachment_image_src( $image_file, $size ); ?>
outputs ‘Array’ in the field, so believe that must be closer to the solution?