In the UK, ‘classified’ is a generic term not a formal classification level. Perhaps you meant ‘confidential’? But in any case, the level ‘restricted’ was taken

In the UK, ‘classified’ is a generic term not a formal classification level. Perhaps you meant ‘confidential’? But in any case, the level ‘restricted’ was taken out of use a few years ago in the UK, and its use indicates that the document concerned is not recent. The current equivalent is ‘official sensitive’