No problem.
I used to write wills for a living. Here's a (very, very, very!) rough draft of the relevant clause:
"I instruct my executors to sell my freehold house, situated at 23a Vincent Road, Potters Fidgett in the County of Surrey. My executors shall have full discretion as to the timing of such sale, as to the advertised price thereof and as to the sum accepted for the transfer of title thereof. I give the whole proceeds therefrom, less the amount required from my estate to pay any such amount as may be owed at the time of my death to any mortgagee in respect of such property (including any expenses incurred in fulfilling such settlements), to Arthur Frederick Smith of 19 The Larches, Treetown in the County of Norfolk"