Late end of year accounts

Hi, i have 3 years of end of year accounts i need to submit to companies house and then hmrc . 3 years worth in total, but i need to do 1 year first then get approval for the next 2. I am waiting for an authentication code to arrive but i can send a copy documents direct to companies house via the post.. I have speaking to them via the phone . I am currently organise spreadsheets from the bank statments.