Could anyone advise if I am required to register and submit a self assessment tax return if I started in June this year? I have has a reminder letter in today reminding me to register and submit by the end of January.
No you dont need one for 19-20 your first return will be due between 6th April 2021 and 31st Jan 2022 🙂
If they are expecting one for this year you need to call HMRC and explain. They used to make you fill it in once it had been issued to you, regardless. But they'll cancel it for you these days if you contact in advance.
Sounds like HMRC set up your record wrongly when you registered self employed (they do that a lot!). If they've sent you that letter, they're expecting a tax return for year end 5/4/20 by 31/1/21. You need to contact them to ask them to withdraw the return, otherwise you will have to prepare and submit one for that year. A quick phone call usually gets them to correct their dates and withdraw the tax return - but to avoid a fine, watch out for a letter from them saying that they've withdrawn the notice to complete a tax return - if you don't get a letter, you'd need to phone them again.