I recently worked an extra day that I'm not contracted to, this was to attend a workshop that I'd been instructed to go to as part of my performance management. Before going on the workshop I spoke to my head of department about additional pay, he said he was unsure whether I was entitled to any, so we sought advice from the union rep who confirmed that I was entitled to an additional days pay. I went on the workshop and completed a form for my additional hours. Upon submitting it I was told it needed to be signed off by the SLT budget holder, he has now refused to approve the request on the grounds that I voluntarily attended the workshop, this is not true - I was told I had to go to meet my target. I work for an academy who claim to acknowledge the stpcd... only when it suits them apparently. Any advice?