Business email address and telephone phone number and email address
Within approximately 10 days, you should receive a letter from HMRC. It will contain an activation code that will enable you to log in to your online account and submit Self-Assessment tax returns.
The deadline for registering for Self-Assessment is October 5th in your second year of trading. The tax year starts on April 6th and ends on April 5th the following year.
You start trading on 1st November 2015 - your first tax year will end on 5th April 2016, so you must register for Self-Assessment by 5th October 2016. Your tax return and tax payments will then be due by 31st January 2017.
There’s plenty of time but it’s better to get it out of the way asap, otherwise you’re more likely to forget and end up with a fine.