Martin wrote:
My son is an Autocad expert amongst other things.

Ah! Another cad monkey ;o)

He also uses Sketchup for work.
He's located somewhere to the south east of you.
The only thing I ever designed was software.

That's good enough for me! Having looked at Rhino, it's far too
'object' specific. My course wants me to work on paper with pencil
first - but I'll spend some time on cad for projects over a certain
scale. I have 27 projects to complete in 2 years - I'm sure I'll find
the opportunity. In the meantime if you come across something
interesting ... think of me )