So many thanks for all of your advice.
I changed the bottle teat to a medela calma which requires bub to make an effort to feed. Two days later he attached to the breast but not for long. The next day I went back to my hospital for a day with a LC. He fed well but painful. Tongue tie diagnosed and snipped same day. 2 days later bub has bf all day with minimal formula top ups. The pain is minimal and the latch is much improved. I'm amazed we've come this far given he wouldn't attach at all less than a week ago. About an hour ago I gave him the bottle and he fussed over it. Swapped to the breast and he has latched like a piranha and drinking happily. Can't believe it! Hopefully this story will give any others hope who read this thread. Thanks again