Remove the meat from the fridge approx. 1 hr. prior to grilling.
To grill the peaches
Charcoal/gas/electric grill: Brush with the maple syrup approx. 10 mins. before the end of the cooking time. Remove the meat from the grill, cover and leave to rest for approx. 5 mins.
Combine the crème fraîche and mustard, stir in the apple and chervil, season. Carve the meat, serve with the sauce.