One reason that these rates are higher than those for equivalent tasks on magazines is that in this sector freelances are frequently taking full responsibility for the job, rather than working to a member of staff such as a production editor. Another is simply that there's more money around in the sector.
The National Union of Journalists must not, can not and would not wish to dictate rates or terms of engagement to members or to editors. The information presented here is for guidance and as an aid to equitable negotiation only.
Suggestions apply to contracts governed by UK law only. In any event, nothing here should be construed as legal advice.