Ok so you're planning to leave, seems to be for the best. Do you have to submit the grievance right away? Not discounting what you've been through and you seem determined to do this - but consider timing. Remember that when you're going for new jobs, you might have to ask for time off to attend interviews and you'd need the HT to be flexible. Maybe invest your energy in finishing your NQT year and getting a new job, where you'd be happier. Could you submit it after then? Get through the next week and have a good half-term rest.