I'm currently on maternity leave and having a bit of a stand-off via email with our business manager about the rate of pay for KIT days.
The guidance I have found suggests that pay should (but not must - it seems to be nice and woolly) be based on usual daily rate. I assumed that this would be 1/195. According to the business manager the daily rate for teachers is actually 1/365 - something about 195 days in school and the rest being holiday?!
I know teachers in other counties who have been paid 1/195 and the NEU said that this would be their guidance too but, as there is no specific law the school don't have to follow these guidelines. The business manager tells me that she is following the rules of the county council (school is an academy) so I'm going to see if I can contact anyone there to clarify their guidance.
I'm the meantime, how much does your school pay for KIT days and (if you're happy to say) which county are you in?