Hi
You would only be able to include an EIS claim in your 22/23 tax return for that tax year.
If your claim is for tax relief on an investment of over £33333, then this claim will need to be submitted on a self assessment tax return (SA100) and be declared on SA101 (additional information).
If you completed a tax return for the year you wish to claim the relief for, you can amend the tax return or if that can no longer be done, you would need to submit an overpayment relief claim in writing.
Please also have a look at helpsheet HS341 at
Enterprise Investment Scheme – Income Tax relief (Self Assessment helpsheet HS341).
Thank you