Can anyone tell what type of lock to use for a bedroom door in a victorian house. But dont want to damage door

Probably what is called a rim lock. The works are contained in an iron box that screws to the inside of the door, with holes through the door for the knob spindle and keyhole. Most houses of that age in my part of the world have 1 1/8 inch thick doors, so a rimlock is usually the only type that fits.

If the door is thicker (1 3/8 inch), a mortise lock is often used. That fits into a pocket cut into the edge of the door.