Gold by Gemini — Jonathan Gash

The British-Roman coins had been around for centuries, so when they disappear from a local museum, Lovejoy has a more than passing interest in finding them. Abandoning his usual pursuits of "good buys" and willing women, Lovejoy finds himself in the much less agreeable company of one Dandy Jack, the sinister Rink, and the lovely, treacherous Nicole. They lead him on a merry chase through a countryside filled with heather--and danger.