Thanks, Snail - I was being lazy asking here for advice! The first link didn't work, but the other two have given me all the info I need. I'm just hoping the leaves do, indeed, die back, because I seem to remember that here in the south-west they stayed green all last winter :). The plant is growing quite vigorously at this time.
Oh well, the rumour seems to be we are in for a hard winter so maybe we will get some frosts this year.
Tricia