Before cooking, pat defrosted meat dry and leave to come to room temperature for 30 minutes.
Preheat a griddle or frying pan to the to the highest setting and brush the loin with oil all over. Place the loin into the pan and cook for:

Medium: 2½-3 minutes per side
Well Done: 4-4 ½ minutes per side

Turning the loin only once. Remove the loin from the pan and place on a rack.
Cover loosely with foil and leave to rest for 10 minutes before serving.

(Typical per 100g)