I don't have any specific experience of schools, but depending on what type of herbicide you're going to use, and with a little thought I wouldn't have thought that there would be too many significant problems. Suggest as a starting point: person applying should have their certificate of competency, something along the lines of PA1 & PA6, and should be familair with all of the main safety requirements including the avoidance of non target species (kids!) chose a non residual weed killer apply out of school hours, such as at the end of the day, weekends or school holidays the HSE site has info on the apllication but probably not anything specific to schools

Thanks phil, appreciate the advice! Bob, It is just general research as to the safest type to use, how and when they should be applied to minimise risk to children/visitors, what kind of certification is required, what level of controls are required etc etc.......