I remember this pic - needs to be a closer up view, can't see leaf/flower detail clearly, even with enlarging. I'm wondering where you got 'flax' from - this is neither the annual flax nor New Zealand flax (Phormium). From this distance, it looks vaguely like a campanula, but the flowers are the wrong shape.

I think someone id'd it before Bamboo... And am struggling with my half asleep brain to bring the name forward. Not a campanula, as you say, flowers wrong... Grrr I'll probably wake in the middle of the night having remembered!

Is it a Linaria of some description ?

Could be Linaria lobatus

It looks to me like what I've always known as toadflax.

I think Linaria lobatus (white toadflax), too.

That's it! My, now awake, brain recognised!

Ah, so that's where the 'flax' bit came from...