If your sofas have well made frames, which I suspect they do, I would get a good upholsterer in and ask for his advice. If he is worth his salt, he will be able to offer you plenty of choice of fabrics and fillings and some of them will even carry out remodelling if you want it. Most of the furniture you buy these days has been made in China and have frames that look as if they have been put together in a 1st year woodwork class. We inherited a suite that came originally from Harrods. It had a hand-built frame and we had it reupholstered, with new feather fillings in the back cushions and new filling in the seat cushions, and it was worth every penny. I wish we still had it. We only parted with it because it was too big for the house we moved to, and we bought G Plan sofas to replace it, which were good, but nowhere near the same quality. If you decide to buy new, get the best frame and springing you can find. If they can't tell you anything about either, walk out of the shop!