Firstly, do you want your baby to drop a night feed. Lots of parents are perfectly happy to do night feeds until way past 9 months old. Your post says about your HV wanting this and that to happen. What about you? Because you don't have to do this, the feeds will not be causing any harm if you are happy to continue.
I would recommend dropping the dreamfeed first.
In saying this I am assuming that baby is being woken up for the 11pm feed, whereas baby is waking you up for the 3am feed.
So firstly stop waking baby and see what happens. The probable outcome will be that he will sleep through to 2.30-3am and wake for the feed as normal.
The dreamfeed will be the easiest by far to drop. Maybe he will wake a little earlier for the night feed, but you don't lose anything since you would be getting up anyway. But DS will be having one less night feed, which can be replaced with a daytime bottle.
While on the subject - aim to replace the nighttime bottles with daytime bottles since your DS will still need the same amount of milk he is having at night, but in the daytime. Milk is still very important for older babies, so don't look to stop all milk along with night feeds.
In the daytime aim to give three bottles a day (morning, lunchtime nap, bedtime?). Him getting him milk intake in the daytime (without decreasing water and meals, milk is on top of this) may itself stop him waking for that 3am feed.