PPi taxable interest on joint loans

Hi, sorry if I'm asking in the wrong place but wondered if anyone can help answer a query on taxable interest from a PPI refund we had a few years ago?

We successfully reclaimed PPI paid on several loans and I knew from the advice on this forum that taxpayers had to pay tax on interest. The bank deducted 20% before payment was made to us so I thought all was well. The loans were all in joint names and payment was made back into our joint account though my OH was the only one covered by PPI as he is the one working and in a higher tax bracket. I am a SAHM, no income/earnings so don't pay tax.

We had a tax demand for an additional 20% which was paid but someone told my OH that I should be able to claim a refund for it as I don't pay tax. As the interest earned on the PPI was in OH name only (even though loans were owed jointly) am I entitled to apply for a refund that anyone's aware of?

Any help appreciated. TIA