Do I send a tax return if it's below £1000

I am currently employed full-time in a job that automatically taxes my monthly wage. My previous employer however asked if I could do some freelance work for them in my spare time. So I said yes and registered as self employed right after. I expected there to be a lot more work but within the tax year it's all come to a total of £747. Which is below the £1000 limit. So I keep getting emails from HMRC saying I need to file my Self Assessment Tax Return before 31st January. But if it's below £1000 do I really need to file a return?

Hi
This link explains who must send a return Self Assessment tax returns