Hi OP.
Your health visitor is probably being vague as a baby’s milk intake can really vary once they start weaning depending how much solid food they’re taking in. Some babies really only play with the food, others wolf it down.
With my daughter she loved her bottle and it took months to notice a real decrease in her milk intake. With my son he went straight on to three hefty solid meals a day and milk intake was minimal pretty quickly.
As a rule of thumb, a 6 month old baby would be having 6-8oz of milk roughly 5 times in 24hrs.
For reference, if it helps, at six months I’d make my daughter an 8oz bottle for each feed (sometimes she’d drink it all, others hardly any.)
A typical day might be a little like this:
8oz bottle at 7am (usually all drunk)
Solid breakfast at 9am
8oz bottle at 11am (may or may not drink it all.)
Solid lunch at 12.30
8oz bottle at 3pm
Solid dinner at 5pm
8oz bottle at 7pm
Night feed at 11pm
(Still having another bottle in the night at 6 months. Usually 6oz around 3am.)
As I said, I’d usually make 8oz but it really varied as to how much of that was actually drunk.
Hope that helps a little!