Hi Matt,
I fully agree with the other comments. It is the mount that enables astrophotography. You wouldn´t even need a telescope. A camera lens will do the trick especially for extended DSO´s like the Magelanic Clouds i.e.
The NEQ6-Pro or EQ6-Pro Orio Atlas are pretty much all the same mount from a company called Syntha. It is the mount of choice for generations of imagers. Sure many venture off to Losmandies G11 later on or fork out Dollars that buy you a german car for a Paramount ME. But the EQ6 is rock solid and carries up to 17kg with ease. It can be guided and there are lots of forums that detail how to tune it even further.
I bought mine at Bintel in Melbourne (and lots of other stuff), was very happy with their Service and would always recommend them.
In terms of telescopes, it really depends on what you want to shoot, how much mgnification you require and how good your polar alignment will realistically be. Shorter focal lenghts give wider fields, are easier to guide, are much more forgiving when your pol alignement sucks and when we talk about a refractor, then they are maintenance free as well. ED80 or ED100 would be my suggestion. Bear in mind that you will need a guide scope and an autoguider as well.
"A friend has a 16" optical tube assembly that is sitting in a cupboard, its home made and is f/20 so very slow indeed!"
Just to get it right, your friend has cupboards that accomodate a telescope that has a diameter of 0.4m and a lenght of 8m?
Impressive cupboard!
Cheers