Spindelina, really sorry you felt let down by the help on offer.....don't just tell us, though, tell NCT. All NCT breastfeeding counsellors are part of a supervision system and you can give feedback to the national organisation (see the website) and it will be followed up.
You said:
"She did reassure me my latch looked OK" - that's good, and observing a feed is something even midwives and HVs often don't do.
"but instead of practical advice about pumping" - she should know about expressing and the different techniques, and have offered to share it even if you did not ask her.
"how to manage small amounts of formula, and general advice on A Plan" - here you are asking for something she may have felt was outside her remit. Using formula with a baby who has already had medical/hospital/midwifery intervention, and whose situation is still under question, may be something that is best discussed with the midwife....but she still should have given you pointers to discuss with the midwife, questions to ask, avenues to explore. I am very experienced and even I would not come up with a definitive Plan (we don't give 'advice', by the way) for you.
" I got a lecture on the wisdom of weighing at 3 days and how dreadful it was that we'd distended her poor little stomach with ebm and formula" If you felt lectured, then she was not doing her job properly. She may have given you the info about distending the stomach, by way of explaining that the volume of formula/ebm your baby had been having was not physiological and you did not need to keep that same volume up. It can be sensible to weigh at 3 days, but it's not necessarily right to tell someone this at the stage you are at :(
However.
The people you should also feel let down by are the people whose paid job it is to ensure your bf gets off to a good start. Babies who end up in hospital because of feeding difficulties have not suddenly become compromised - you had days of midwifery care, and they missed the problems.
Yet you come on mumsnet and describe the shortcomings of a volunteer who you are asking to clear up a situation caused by (or at least ignored by) the paid professionals. I agree the bfc was less than what you needed and her manner sounds poor, but if you are going to feel angry and upset, make sure your anger and upset also include the midwives and others.....and the hospital too, who discharged you without a plan. That's their job, and they failed.
Complain.