Best place to try out couches in the area?

Looking for somewhere with a lot of options to try out so I am not buying a couch I have never sat on. I've been to the Next in High Wycombe and know they have furniture there. Is that the biggest Next in the area? Any other good stores that are comparable? Looking to spend under £2k and get something that is good quality, deep, and you could fall asleep on because it's so comfy.