Thanks all!

The Paed doesn't think there's anything really wrong with him -- and I do tend to agree in that he doesn't seem in pain during the vomitting, although there is a lot of it and it can be an hour after the feed ....
He is grunting and groaning a lot -- mostly wind -- again can be after an hour as well.
He is gaining weight well etc.

I have Avent bottles, tried their number 1 teats, Pidgeon number 1s and now I am on Happy Baby Y. the number 1 teats just seemed to constantly drizzle in his mouth ... that is why I changed. Do you think I should try to go back to them?

I kinda feed to schedule in that it is about 3 hourly. However, if he's really hungry, I don't hold off the bottle. There are times where he only takes half or less and sometimes the whole thing. The MCHN said that this was fine though ...

That is really interesting that the acids work after 12 hours ... DS does fuss at the bottle -- maybe doesn't like the taste?

Now that it is 9am, I will try calling the MCHN about it also.