Hi,
Payments on account are based initially on your tax liability for the year before.
They are merely a starting point for tax liability for 23/34, as no-one knows what going to happen in the future.
Payments on a accounts are 'fluid', as they can go up in a good year and down in a poor year.
You will need to project what your gross income from property is likey to be and the expenses you expect to incur, to work out how much tax you are likely to have to pay for 23/34.
You can then increase or reduce the payments on account accordingly, even make them £0.00.
If you do not pay the July payment on account, self assessment will automatically issue late payment penalties to you and charge interest on them.
On receipt fo your tax return, your tax liability will recalculate the payments on account and adjust the late payment penalties accordingly.
If there is no late payment, the penalties would be cancelled:
Understand your Self Assessment tax bill
Thank you