Every special school will have to make their own decisions. The advice from government is unworkable. Some factors are:
Government says there should be a place for all children with an EHCP and schools should reduce number by only taking a few pupils (but all special children school pupils have EHCPs - so to reduce numbers, they cannot take all pupils).
Special schools can only operate with a high staff ratio, if staff are self-isolating, not all pupils can be supported.
Pupils have specialised and trained support, therefore an even higher staff ration is not needed (do you want your child hoisted by an untrained person? ditto, feeding, behaviour plans, physio support, etc, etc)
Special schools have very high levels of adults, therefore are a risk of spreading disease).
SEND pupils often have medical issues (cerebral palsy, epilepsy, heart conditions, swallowing issues, etc etc, and are therefore more vulnerable.
Staff will be working over Easter holidays - burnout must be avoided.