I have considered that he is an efficient feeder, though my breasts still feel very full after the feed.
Thanks for your replies. It has certainly helped.

I'm not sure if he's gaining weight as I don't weigh him regularly. Perhaps that's something I should do. He's quite lean. I wouldn't say underweight but he's definately not the chubba bubba DS1 was.

He has 4 or 5 feeds a day. If I offer at other times he'll either refuse or just suckle for a minute or so.