Can SMP paid at a wrong rate be fixed retrospectively (prior to filing to reclaim)

My small Ltd company has a director and one employee. The employee was on maternity last year March 2023 to November 2023, so mostly in 23/24 tax year. During this period she was paid statutory maternity pay + top up (matching pre maternity pay). As I was looking at reclaiming the SMP from HMRC I found out that the accountant running my payroll has made a mistake and used the statutory maternity pay rates from 22/23. This equates to about £500 difference. When I raised it with the accountant, they basically said "Oh, yeah you are right but it's too late to fix it. Sorry." And that was that. So is it really too late to fix the error?

Hi, 
If you have reclaimed it through your payroll then you can just send in and EPS for the previous year to correct the amounts.
Thank you.