Major Sinclair starts the first day of Colonel Barrow's command still wearing his previous acting Colonel rank. Half way through the day (between the assault course and watching the pipers), his rank changes to Major. Whilst it is possible he might have had his jacket altered over between the scenes, it is not possible that Colonel Barrow (a stickler for uniform regulations) would not have mentioned this at the start of the day.
When Jock is driven from the barracks in a jeep at the movie's conclusion, the rear seats are green. When the jeep is seen externally a few seconds later, the seats are white.
When the Colonel drives off into the night after the dance, his jeep is the only one with headlights on. The drive through the town shows others vehicles with no lights and many people just walking around shopping. Finally driving to the lake there is a car following them with no lights and the light at the lake is an pleasant afternoon as it was all filmed during the day with a filter on the lens.
At almost no stage does the bagpipe music we hear on the soundtrack match the pipers' fingering we see. In addition, during the band practice scene the band goes from being in step with the music (first beat of the bar on the left foot) to out of step to back in step again.
Pipe Major MacLean is never shown with a set of bagpipes. In particular, he is a mere observer at band practice. A pipe major is not only the leader of the band but also its chief instructor, and it is unthinkable that he would not play an active role in all practices.