Window sash repair

Going through some basic timber window maintenance and have identified several areas of woodrot, detailed in the pictures. Beyond my DIY capabilities. The timber sash in the first image has some damage on both ends so I believe the entire 1000mm needs to come out. Have also included a picture of a window frame missing a slither of timber as well as a nearby weatherboard, which I would like fixed at the same time. Flexible on how quickly to be done, the sooner the better but not desperately urgent.