The accounts include not only Fairbairn’s private patients but also payments from other sources including the Ministry of Pensions and Edenhall Hospital.

The account books are not all of one format but in each is recorded the following information: the billing date; the name of the person or organisation billed; the amount billed; the date the bill was paid; the amount which was paid; and, where applicable, if the bill was outstanding, carried forward or written-off as bad debt. MS.50153 also records the patient`s number, which was assigned by Fairbairn and recorded in his chronological list of private patients, MS.50166, where this is applicable.

The accounts are arranged on a revenue accrual basis, rather than by the date the payment was received. The accounts are cumulative and at the end of each financial year Fairbairn`s outstanding debts are summarised, although this is a practice Fairbairn would appear to have stopped after 1960. The summary includes the date a debt was eventually paid or, if left unpaid, that it is was written-off.