Shade could make it green out, but also many shrubs which should have some variegation don't have it.
I think our weather is not often much different to yours Magga! It seems we get cold winds from the north more often than the south, if you look at a map we are not much below you!
I have a similar Hebe, I had two which got too big for the place I had them in so I removed them but I have one which grew itself obviously from seed nearby. It's now mature, but I rarely see flowers on it. It survived our winter 2010/11 when we had 7 weeks of continuous frost down to -17C, one day was a maximum of -7C! The shrub wasn't at all damaged by frost.
