I've been out of town for a few days and didn't have a wireless connection.
I think you'll find the use of "guard" loads (reduced power practice loads) were actually in existence in the US also. Most of these "guard" loads were for .30-06 and other rounds, that existed around the turn of the 20th century, very much prior to the introduction of the .308 WCF.
I actually use quite a few subsonic loads, i.e. 12.0 gr of Green Dot in .45-70, that are much more useful than a .22 rimfire of any sort.
