Hi,
Which tax year bookings for March 2024 as well as building management or service charges, insurance and utilities are to be accounted for, would depend on the basis you are using for the furnished holiday letting (FHL).
If you are using the cash basis, then receipts and expenses are accounted for when the money is paid, whereas, the traditional basis, you would declare these when they have arisen or been incurred, for example March 2024. As long as the property is only used as a FHL and not occupied by yourself, these would be allowable expenses.
You can find further guidance on cash basis for FHLs in PIM1092.
PIM1092 - Cash basis for landlords: overview
Thank you.