Appropriation of property from Estate - expenses

I’m acting as tax advisor to the executors of an Estate, who are the son and daughter of the deceased. One of the properties within the Estate is due to be appropriated to the beneficiaries (also the son and daughter). The executors extended the lease of the property a couple of months ago (during the period of administration). I’m trying to establish whether they could claim any deduction for the cost of the extension, on a sale by them personally. The property will sell for a gain compared to probate value. I appreciate that s64(1) TGCA 1992 allows a deduction against the sales consideration for the costs of transferring the asset to the beneficiary, which I expect would not encompass the earlier cost of extending the lease. However, I was unsure whether there was any possibility of a deduction under s38(1)(b) TCGA1992 as the expenditure on the lease extension could be said to be incurred on behalf of the beneficiaries in enhancing the value of the asset. I’d appreciate any views on this, thanks in advance.