I couldn't find a solution to this. Similar to the question raised here.
But I adopted another angle of how to display my form which I think is worth listing. As the form I wanted my user to see is pretty much the same as the one I already had in Admin for the entity then I changed the permissions for the front end users Roles to be able to see and edit the form.
I then used Pathauto to change the URL of the path, as the former path had '/admin/structure' at the beginning which I wasn't happy with.
And finally to add and process some other areas of the form that I wanted to was to user 'hook_form_FORM_ID_alter'
So if you searching for things like
drupal 7 Price with currency widget for form
drupal 7 form api example of '#type' => 'commerce_price',
Then maybe you to like me where barking up the wrong tree !!