Gazz

Your Lats are pretty large muscles and require some beating to stimulate an anabolic recovery.Chin ups,wide,close grip and straight arm pull downs are my weapons of choice.Not all on the same session.Week by week.Form is an important factor too.Nice straight back,squeeze the muscle at the bottom of the pull,contol up.There are way too many 'swingers' on Lat machines these days.All they will grow themselves is a nice hernia and not alot of Latimus.They are also the first muscles you should hit on back day IMO.They require the most effort and need the best part of your energy.Thats not to take anything away from bent over rows so to avoid getting into a rutt these two exercises should be rotated with each other maybe.

What issues are you having with your biceps?Apart from the obvious!