Carrot Cake

We are going to be closing our Ltd company, it has been incorporated for just over a year, but we have not made any money. We do have a bank account, but the only money is money from our personal funds which we used to pay for hosting and incorporating company etc. At the start we went through the registration for Corporatoin Tax purposes and have email confirmation, and a email from HMRC acknowledging and saying if any further information required, they will contact us. We didnt hear further. We now come to close the company (business just didnt go anywhere, ended up having no time for it etc.) and when we go to log into the Government Gateway to find out what the requirements are, there is a notification that we are not registration for Coporation Tax purposes. We want to ensure we do it right. It seems as though before we do the forms with CoHse we have to make sure HMRC know about the company closing. Do we need to file final accounts (we dont need to yet for CoHse purposes), as we have effectively not traded? How can we tell HMRC without having to register for Corporation Tax (which thought we had done, but it seems not)? Thanks so much