Where should it go? Do you fit the architrave right up against the edge of the door liner? or Should it be set back by 2mm? I have seen both options used and wondered if there is a right/wrong location, or is it down to personal preference?
I set mine back by 6-7mm as this is what they were originally fixed at. http://community.screwfix.com/threads/door-architrave.177538/
I was taught 5mm in. Some old school used to fit flush but it is extra work then Plus set back looks nicer
Usually set about 1/4" (6mm) back. The reason is so you don't have a "paint line" when it's decorated and it doesn't get in the way of the hinge knuckle. Also aesthetically it's a lot nicer.