Paddy,
First let me say that I completely agree with you about the HP printers. I love my Photosmart 1000. I also agree with you assessment of the Epsons. However, you may be able to resurrect that 850. Here is what I did with my old 740. I had/have an Epson stylus 740 that had become completely useless because the print heads had become clogged beyond use. The printer would just bang around and refuse to even attempt to print. This was probably my own fault because I had been using aftermarket ink cartridges in it. Regardless, I got it working again. I actually removed the print heads from the printer and soaked them in Acetone printed circuits and all. I know what you may be thinking, the print heads are mostly plastic and acetone eats plastic. Well, I decided who cares the printer doesn't work anyway. I let it soak for about a half hour and then thoroughly rinsed with water. After allowing them to dry, I reinstalled them. I then put a fresh set of Epson branded cartridges in, and the printer has worked like new ever since. That was about two years ago.
I still use the HP for most things. However The Epson always works when called for.
P.S. a couple months ago my Step dad gave me four black epson cartridges that were supposed to go into a Stylus 4,5,6,700 printer. They are not intended for the Stylus 740. They do not even fit properly in the Stylus 740. They are too small. However, I put one in anyway and it has been working fine for over a month now.