I think that it was only the later facelift SE Nav, Diamond and Exclusiv models that had factory tints on the rear and back windows. I am not sure what year this was applied from but my 2015 SE Nav has them. I also know that Vauxhall no longer supply the interior clip in privacy/sun shades for side and rear windows that they used to if you did not want to go down the permanent tint film jobby. However the Bay of Flea does have them.
2015 SENav Auto in Stormtrooper white