Okay, so I seen the GP today. He said DS is perfectly healthy, he has no concerns about his weight and he is definitely well hydrated. The only problem he has is a bit of dry skin and lips which he gave me cream for. :)
He said that I can offer water between feeds to keep his mouth wet if I want to but I do not have to give him water as he is well hydrated. He has no concerns at all about his weight or that the amount he has been feeding has had any bad effects.
He also said he spoke to the HV and she said to him that my house is very warm and she keeps telling people that "DS looked like a lobster when she came", the GP replied that "lots of houses are warm so that doesn't make a difference at all". Also, the time she is referring to she had just made me get him out of bed and wake him up and strip him so he was about to cry and that's why his face was red. 
Jennifer 50oz per day!
And yes, it is hard to keep up with at times.
I wasn't a big baby but DP was, he was 9lb 2oz. We really expected our LO to be quite big too and were told he would be at a growth scan before he was born, it's just he was born that little bit early. :)
SkinnyJeans Exactly, you can't force feed them and there's no way I am willing to remove feeds and have him scream for hours. I trust him to let me know when he's hungry and I will listen to him and not some crazy stranger who thinks I should let him cry it out.
Lilham I think it is now clear she is definitely trying to undermine me because of my age, which quite frankly is crap. I know lots of people who are much older than me that I wouldn't let near a child. Age really is only a number.
Pozzled, Rita and Lilham Thank you for helping with the charts, it has been extremely helpful!
Crikey I am now considering sending a letter suggesting further training. She really did upset me and if I hadn't been the type of person to question her 'advice' then I might be upsetting and withholding food for no good reason.
Thank you everyone for being so nice and helping so much. I know I have posted many threads on MN in the past months and I am always overwhelmed by the amount people are willing to help. :) I really do very much appreciate everyone's replies. :)