Near Cranwell: The Hare & Hounds at Fulbeck and the Hooblon (sp?) Arms at (forgotten) used to be great before pubs became food factories.
Near Coningsby: The Abbey Lodge near Woodhall Spa, as above.
I think I'm right in saying that access to the Ram Jam Inn is now a bit difficult going south as you have to drive 600 miles to the next turning point in the dual carriageway barrier.