Sorbus Autumn Spire final size?

[HiluxMan]

Does anybody have a well established Sorbus Autumn Spire rowan tree?
I am trying to find out what the fully grown width of them is to see if we can fit one in the garden.
Everything I've read so far ranges from 1 metre to 3 metres and some sites only tell you what size it will get to in 10 years rather than when it's fully grown.

[davyp1]

My tree has been in just over 8 years now and is about 4m high and has a girth of about 60mm near the base. It's crown is only about 1m wide and is really quite a delicate and attractive tree.

Some of the single specimens shown on the following link are indicative of mine:

https://www.google.co.uk/search?q=Sorbu ... ved=0ahUKE

Davyp1