On the BBC News today the 0.5M trees in question are being described as being Sequoiadendron. In the UK "(giant) redwood" is synonymous with Sequoiadendron - http://www.redwoodworld.co.uk/
So that doesn't really clear up the issue. I think it is safe to say that there are some sodding large trees in the UK that originated from the US. Many of them will grow really, really tall. Given that there are "only" 80K S. "Big buggers" in the US and around 0.5M assorted "Redwoods" in the UK, there is a good chance that there are more S. "Rather large" here than there. Ours are the result of deliberate collection and planting. We also have a large number of Monkey puzzle trees too which I think originate from S. Americas.
So that doesn't really clear up the issue. I think it is safe to say that there are some sodding large trees in the UK that originated from the US. Many of them will grow really, really tall. Given that there are "only" 80K S. "Big buggers" in the US and around 0.5M assorted "Redwoods" in the UK, there is a good chance that there are more S. "Rather large" here than there. Ours are the result of deliberate collection and planting. We also have a large number of Monkey puzzle trees too which I think originate from S. Americas.
Just up the road from here: http://www.redwoodworld.co.uk/picturepages/yeovil.htm