It's a Philadelphus, probably a form of P. lemoinei, but maybe another.

More likely to be a eucryphia if it's flowering now

Isn't it Beautiful :o))

It is beautiful! And Andrew is probably right, Eucryphia is a better fit, now that I know what to look at. I can't see the foliage very well, or I would make a stab at which species.

Oooh. Looked it up in order to see if it would go in my garden but it gets too big. Does it survive where you are Roseberry?