HMRC Tax Refunds

I make a lot of donations and in past tax years, I have received refunds from HRMC. It is worth noting that for those years I worked with a big 4 for self assessment.
This year I realized I technically don’t have extra income and so don’t need to file for self assessment and cancelled the self assessment with HMRC.

How do I check if I can still get the tax refunds from
HMRC?