I was a frantic mothers with a 5 min feader, I gave up breast feeding because of the constant worry that she wasn't getting enough. My HV also kept swearing that there was no way she could get enough in 5 mins of sucking!
She is now 5.5 mo and I have just regretfully moved to formula, and after some shouting and wriggling and some small feeds, tried a fast flow teat. She can actually put away 7 oz of formula very happily in 5 mins!!!!
So just thought you exasperated and lucky breastfeeding mothers know!