Sissy

I want to complete an online self assessment form but I have lost my Government Gateway account user ID and password. I can't find my ID in old emails though I can find a Gateway Registration Notification email confirming that I have registered. When I follow the instructions to recover the ID and password, I get as far as confirming that I am not a tax agent and that I want to access 'Self Assessment' with my account. The first security question I am asked is for my UTR. When I provide my UTR (which I do have) I get a message that says: 'The information you gave us does not match an HMRC record'. If I try again I get asked the same question and therefore cannot get any further in the process. Can you help me get beyond this point, please? In the past, I have had a tax agent who has completed a self assessment form on my behalf. This year I want to do it for myself. I wonder if this is why my UTR is not associated with my email address? However, I cannot disassociate that tax agent from my self assessment form without getting in to my Government Gateway account. Catch 22! Please can you tell me how I overcome this problem so that I can complete my self assessment form on time? Thank you.