I did, and they have lasted 6 years! We are replacing them this year.
The onyl thing I found is when they arrived they were quite a bit smaller than I imagined. I measured and thought they would be fine, but by the time the arms were taken into consideration, they were a bit tight. Other than that they've been fine, now changing as we need bigger ones.
I bought 2 sofas from MFi, couldn't drive at the time, so jsut ordered online. But thinking back further I did order one from a catalogue with exh. That was fine too, though a lot bigger than we expected and a slightly brighter colour.
Normally large items from online ordering charge a restocking fee. Looks like gratton charge £12.95 according to their website.
It might still be worth looking around the furniture stores though and sitting on a few. We recently ordered our new sofas for about half price from furniture village and have requested delivery in dec, so we can spread out paying for it a bit.