Could you tell me what happened to you in the end as I am going through the same thing now, Im so scared of what will happen. I hope you dont mind me asking. Im just about to post a letter to them as i cant get through on the phone,(thank god as i feel sick when i ring)

Hi I'm in the same boat, I got married in July and haven't told them, got a letter yesterday saying they knew there was another adult living here and knew his name. Again its my own stupid fault but feel sick with worry, as he lived here before then and I did not tell them all be it only a couple of days a week. The house is his and i started renting it from him as he lived away,then we started seeing each other, I'm so scared they will find all this , they are asking for tax year April 13 to now. I've tried ringing g them three times but can't get through