In the top photo, we see one gentleman (with the purple hose) with a jacket that, while interesting, is really neither traditional nor classic for the kind of daywear that usually involves a necktie. It might be fine for shooting, even the kind of shooting that usually involves a necktie, but it is not a traditional day dress jacket. If one were to sport such a jacket and tie with trousers, people would call it a "leisure jacket" recalling the 1970s disco era... Standing in proximity to the Duke of Rothesay does not make this man's dress any more traditional.
That would be Lord Semple, and if I remember correctly. It is not a '70s "leisure jacket", but more akin to a sack suit of the mid 19th century. There are a number of photos of the Balmoral Ghillies in the mid 19th century wearing something similiar. I can't find a copy at the moment, but the picture I am thinking of is featured on the back cover of Bob Martin's All About Your Kilt.

It's certainly not from the 1970s though.

T.