Is anyone growing this tree?

Not here in the UK Andrew, but yes, grew it in North Eastern Spain. I grew it in our hillside garden which had very poor, stony soil. We did introduce an irrigation system which helped a great deal. Facing north-east it grew to about 6ft in 3 years, but would have done much better I'm sure in richer soil. In the spring I would dig in a good helping of sheep manure to give it a boost. Those little fluffy tufts were a picture to see in the evening light.
Temperature wise, winters did descend into the minus temperatures and it survived well, whereas other trees like the Jacaranda didn't.