Cover teachers and strikes

Firstly, sorry if this is the wrong place to put this, I have no idea where else it should go.

With the NUT strike tomorrow, my school is remaining open to Years 7 and 11, but we have received very little information on what they're planning on having us do. I don't think we can follow the normal timetable, because some of our teachers are striking. My school seem to think they can deal with the issue of not being able to cover striking teachers by having the SLT (senior leadership team - the heads) cover our lessons, but I was under the impression that the law was nobody is allowed to cover for striking teachers - at least, that's what the NUT website says. Does anyone know what the law actually is, and if my school are allowed to do what they seem to be trying?

You are probably not interested in the answer now but members of Leadership are not covered by the School Teachers' Pay and Conditions Document so have to cover. Mr Gove pressured Headteachers to deploy volunteers to break the strike but was completely ignored.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/279601/advice_on_handling_strike_action__2_.pdf