Apportionment of costs query

[BobfromDevon]

Some hopefully simple straightforward clarification needed please.
My wife and I have been lucky enough to own a small second home in Devon for some years- using it as a holiday home for out own use only and not as a business.So we've previously had no income to declare from it and have born all the running costs.
Last year (June 2021) following retirement we bought a new main home elsewhere in Devon following which we soon realised the second home was no longer being used as or needed as a second home for our own use and we decided to let it. Agents were instructed just after Christmas and it has been let (at a fairly modest rent) since February 2022.
We are well aware that we will have to declare the gross and net property income we earnt from it for the tax year 2021-2022 and going forward.
The gross income is what it is - the rent received since February 2022. But what costs can we actually claim for the 2021-2022 tax year? Obviously we had to incur Council Tax, utiliies and other costs for most of the year until the property was let and most of these costs became the new tenants liability. Between deciding to let it and whilst it was marketed and prepared for letting and after which we had stopped using it ourselves there were quite a lot of costs bringing it up to lettable standard. Can we claim for those costs for some or even all of the tax year 2021-22?

[pawncob]

https://www.gov.uk/hmrc-internal-manuals/property-income-manual/pim2505