This is an operational matter for which the management of Post Office Ltd. (POL) have direct responsibility. I understand that this branch currently has a fee paying ATM. The site has been assessed by POL and their venture partner the Bank of Ireland and this is a site where they want to place an external free to use ATM.
I also understand that the subpostmaster has been sent the contract and terms and conditions, and POL are currently waiting for them to return the signed paperwork.