Then a friend gave me some gorgeous woolen fabric that looked like it'd be big enough to make a slipcover from. Surely cheaper than proper reupholstering and hopefully a fun project :-)
I'd started by attaching cords to tie to the front legs of the sofa, with the cords attached to pieces of tape to spread the strain.
Then I'd sewn the front corners, in the process cutting out a roughly square piece of fabric from each.
Next came a cord to keep the fabric snugly in the groove between the seat and the back.
I cut the fabric in line with the cord at each side so that it could sit smoothly on both the seat and the back. I filled the V-shaped gap thus formed with fabric that, had I not cut it off, would have been hidden under the wood that supported the arms anyway.
Lastly I needed to tidy up the back. The fabric wasn't quite long enough to go over the top of the sofa so I attached some black calico to extend it. This actually took about as long as the whole rest of the project as it involved lots of hemming! Once attached, I stitched in the folds on the top corners of the sofa, in the process stitching the squares I'd removed from the front corners onto one of the sides (it turned out I hadn't attached the fabric to the sofa as symmetrically as I'd thought...).