Tax relief on private pension contributions

SunnyBunny

Just over half way through 23/24 tax year I had approx 30% salary increase due to promotion, so until then I paid only 20% tax.     I only received notice of this underpayment this week, it is based on reducing personal saving allowance to £500 and another £100 underpayment + £103 from another year.     I am still an employee & do not have to do a self assessment. 

I will give HMRC a call this week and see what the deal is re any refund.

Thanks for your replies.