NotanOtter, you say " I do try not to let him go less than 3 hourly but never more than four and he feeds for as long as he wants - i often get two let-downs during a prolonged feed/cuddle... "
You'll get letdowns you aren't aware of - counting letdowns doesn't really reveal anything. Many babies feed more often than three hourly, and it's quite normal. If you count up the no. of teas, coffess, biscuits, snacks, meals, an adult has, it's prob more than every three hours. I've had three cups of tea, one cup of coffee, 2 slices of toast and a biscuit myself - all since 8 am, and all staggered through the morning!!
"Again - he was constantly on the boob when a different HV ( when he was 10 days) said do not let him feed more than 3 hourly - 'only gets foremilk etc)"
She's talking rubbish. Complete and utter. Forget the clock.
"I calculated ( estimated due to exprssing) that he gets 36 oz - 38ox a day - what does that sound like ?enough or not???"
But expressing is not a way of calculating what the baby takes - the baby might take a load more or a load less. All it reveals is a calculation based on what you managed to express at one particular time. It's irrelevant, truly!!
Just feed him more often (if you think there is an issue with his weight), and take no notice of what 'advice' you get from HVs.
:)