Ah right, I would assume that as long as it covers both outcomes from the Nat 4 unit assessment then it would be perfectly acceptable, however, you would have to have your assessment verified before it was valid.
The guidance does say (page 6) a “series of webpages using a web authoring package” but that is for the unit assessment supplied by SQA. As for the media types all that appears to be required at Nat 4 is text and graphics with links to related information.