Gwynnethmary,
The flowers do not get any bigger and they seem not to be flowers more like pollen sacks.
Bugloss2009,
I don't think its a form of Bupleurum as they have these in the garden too.
We are still at a loss as to what this is and have found it is a climber which is not invasive and does not grow more than the size of the trellis in height and spread. Which is 6' high and 3' wide.