Cleaning Staff are paid from an ancillary grant, which is given to all schools by the Department of Education each year based on the number of pupils enrolled in the school the previous year. This grant is also supposed to cover the wage of all ancillary staff including secretaries, etc. but, in general, it doesn’t cover even one of those costs unless a school pays less than minimum wage. For whatever reason, secondary schools receive a higher rate of ancillary grant than primary schools no matter what their size.
Effectively, cleaning staff should simply be paid directly by the Department of Education through contract cleaners. Local cleaning contractors should apply to clean clusters of schools and the contract would be awarded by the Department of Education for a certain amount of time and that would be that. All supplies would be provided and managed by the cleaning companies and there would be standard process to go through when there are any issues etc.
The current system, while it might be nice, is extremely expensive and nobody is paid to manage it. Having a central procurement system would not only be good for the local community as it would create jobs in local communities, it would also be much more cost effective.