I looked further into this and found out that medium_large size was introduced by wordpress after 4.5 and the only way to get rid of the unwanted thumbnails is to add some code like this in the functions.php
function add_image_insert_override( $sizes ){
unset( $sizes[ ‘thumbnail’ ]);
unset( $sizes[ ‘medium’ ]);
unset( $sizes[ ‘medium_large’ ] );
unset( $sizes[ ‘large’ ]);
unset( $sizes[ ‘full’ ] );
return $sizes;
}
add_filter( ‘intermediate_image_sizes_advanced’, ‘add_image_insert_override’ );

so will you be able to supply me the code for this and also your theme one called shop_catalogue_x2 to add in my child theme?

Thanks