This guide is based on myTechTalk thread "Duratec R400: removing/repairing/replacing wet sump" (April 2016).
I'd managed to hit a large rock in the middle of the road, resulting in a cracked sump. As luck would have it, this happened just two weeks before my planned trip to France (to include the Grand Prix Historique in Pau). My immediate plan was to remove the sump, assess the damage (just a hairline crack, I hoped) and get it welded. If the damage couldn't be repaired, I'd be looking at a new sump pan.