I need some confidence in phrasing my request successfully. I am employed by an agency and have completed one year working supply (teaching) for them. I have been reliable and school's have given good feedback. My rate is fair although considerably lower than when I did supply work in London several years ago. One school I was at took me on for two regular days a week last year and also booked me for lots of additional supply. I'm about to go back there for one day a week booked through the agency. I think this would be a good time to negotiate.