The style of all apart from the grey/yellow label on the bottom left (which is more modern) would have been introduced as part of BR's corporate image from the mid-60's.
The no smoking penalty fine (£50) is from later than the 70's, as the original circular labels would not have had a penalty fine listed.
Certainly until many of the carriages had gone through refurbishment from mid-late 60's through the 70's, the labels/transfers from earlier (e.g. red triangle no smoking and long blue 'FIRST') would be much more prevalent.