Thanks Lin. I've just done a bit of looking at the varieties of jasmine and suspect it's Primose Jasmine (jasminum mesnyi), as it fits the following:
- Grows as a creeper/vine/climber up a tree
- Height is around 3 metres
- In flower now (late winter)
- Evergreen
- Unscented
It's also rooted itself in a few places (as per the comment on the Primose Jasmine in the database).