From a legal perspective you can’t be expected to pay rent to a then previous owner for the days following transfer. With the uncertainty of actual transfer it is reasonable to expect to pay full occupational rent to the lawyers and receive pro-rata refund where required.
In addition, depending on your bank, in my case, if the registration occurred after the 10th, first repayment only occurs in the month end that follows the month, i.e. end Jan, which is a pleasant reprieve with your planned renovations