You almost certainly need 2 people.
Try the GB Owners Forum for a hull surveyor. Someone here could post a link for you.
The Ford Lehman is your basic simple normally aspirated diesel,unless you have the turbo version and not the common 120 or 135hp versions,which any decent mechanic could do.
Among known issues,coolant passage silting around no.6, raw water pumps with drive tang which can break without warning,(updated version available). Check if the coolant overflow tank has been updated and an overflow bottle fitted(ADC kit available)
Maybe American Diesel Corp,successors to Lehman,would know who in Maine buys lots of Lehman parts.
Of course, you could ask the broker for suggestions, but...