TEACHER shortages were this week compounded in many parts of the country by flu. Schools, already suffering the effects of the recruitment crisis, were forced to send pupils home when large numbers of staff called in sick. Supply agences said demand had been so great that they had been unable to fill the gaps. One of the worst hit was Warden Park school in Cuckfield, West Sussex, where an average of 300 pupils and 13 teachers were off each day last week.