Plain English is perfect — write it the way you'd explain it to a new member of staff.
e.g. 24 residential lets, 3 HMOs, 2 commercial units
Amounts, collection day, and how you chase arrears now
From tenant report to contractor to invoice
Gas safety, EPCs, deposits, inspections — and their renewal dates
The workarounds, the spreadsheet on the side — that's the part we tailor around
Monthly fees, per-use charges, commission — whatever you pay