Seafarers Earning Deduction

My daughter worked on a cruise ship from November 2023 till May 2024. Currently on leave and is heading back for another 6 month contract in August. She is currently working on her accounts ready for self assessment for the year 23-24. She has already paid the payments for this year in both January and July. When she does her self assessment due January 2024 she will have gone over the 356 days period and would probably have paid too much tax for 23-24 though will probably still be required to pay another 50% on account by end of January. If she applies for SED in November when she reaches the 356 days will this be in time to stop her having to pay 50% in January.

If your daughter qualifies for SED, her income from November 23 to April 2024 would be covered by the allowance. Any other income from April 2023 to the start of the claim would remain taxable, and this tax would be payable by January 2025.