Jaguar S-Type a droning noise

Worn wheel bearing .

I didn't think of that I as its not long since mot I thought may be diff or torque converter

Every chance an MOT would not pick up a worn bearing if just noisey unless badly worn and excessive movement , limited to what you do on test .I would think torque convertor very unlikely , could be diff .Try driving car and then throwing to one side then the other and see if noise varies when load transferred .Just be careful where you do it , quiet , clear road .