£75 seems abit steep just to fit a door. I realise in a newish house its much easier than in a country cottage. I ask for around £35 per door in modern house and £45 (both plus hinges etc) in old properties to allow for extra work involved. Quite often see 5" hinges and surface mounted locks. Also jambs, floors etc aren't straight. Just out of interest which is best if the frame is out of square at the top and side in a 100-200 year old cottage ? Cut door to side or top ? I ususally go for cut the top and put in straight to the hinge side (if you see what I mean).