Seb was having doubts as he trudged up the spongy mud track toward the sea. It had rained steadily throughout his journey from London to deepest Cornwall, and now that he'd been forced to abandon the Audi — the single-track road he'd been following didn't reach all the way to the cliffs — he was soaked through. Blobs of rainwater covered his glasses, reappearing seconds after he wiped them away. The grasping mud had already ruined the Jimmy Choo Italian leather loafers he'd given himself as a present after…