For various reasons, we've only contracted with our builders to do our loft conversion up to the point where we will have stud walls, a floor, first fix electrics and water and insulated external walls.
I asked them to quote for finishing it off (they won't do bathroom fitting so I will have to find someone to do the final plumbing for me) and they suggested just over four grand to plasterboard, plaster and fit doorframes/doors. It's not an enormous loft conversion, maybe around 25 square metres when it's finished, one bedroom with an en suite. Four grand feels like a lot to me, but I really don't know if it is? I was thinking of getting people in on a day rate to finish it off, but not sure if I'm just being hopeful that it will be cheaper.