HMRC allows you to use tax reliefs against previous years’ tax liabilities. If you have already paid tax for a previous tax year and have now reduced tax liability using a relief, you can claim tax refund from HMRC.
However, you must provide proper records for both the current year tax liability computations and the previous year tax amount that is to be re-adjusted. This is why HMRC requires businesses to keep business records for a minimum of 5 years.