West Sussex,
United Kingdom 
Hebe Addendum.
I was given this plant about 15 months ago and left it in it's pot to overwinter on the patio. I really thought I had lost it as the frosts turned all the leaves nearly black and the whole plant was bare and ill looking in the spring. I repotted it and it has gradually recovered. Does this mean it is not hardy or did it nearly die because it was in a pot and not in the ground? I have stood it in the porch for this winter but it takes up a lot of room. If I plant it in the ground next year will it still need protection?
17 Nov, 2017
Answers
Thank you Bamboo. It didn't flower this year although the foliage recovered well. I'll find a spot for it and plant it in the garden in the spring and just hope for the best.
18 Nov, 2017
According to Dobbies, this is rated H4 for hardiness, which means down to -10degC occasionally, but in colder gardens, or gardens with heavy, wet soil all winter, it may well keel over. They also warn that the topgrowth may die back in a cold winter, but if your soil is reasonable and you can find a relatively sheltered spot for it, it'll likely be fine.
17 Nov, 2017