I would take it to mean that:
a) you don't get paid for school holidays, and
b) �11,403 is the rate for a full time worker and isn't what you'll get for the time you work. For example, if the normal hours for a full-time worker are, say, 39 a week, then you'll be paid 30/39 of a full-time worker's weekly wage.
The best thing to do would be to check with the person who placed the advertisement to see what they meant by it.
it would basically mean that you would get paid the hourly rate of �11,403
pro rata basically means at the rate of
so if a person is on �10,000 a year they are basiclaly gettin paid about �5.00 per hour
so a person doin a job at �10,000 pro rata for 10 hrs a week would be gettin paid the �5.00 (or whatever) per hour for those 10 hours
instead of advertising the job as �6k per annum (30 hrs a week term time only) they haev advertised it as �11,403 pro rata (30 hrs a week term time only)
and thats the difference:
per annum is "per year"
pro rata is "at the rate of"