Pretty sure the Wilson Augusta irons were a store line club. The Power Groove that was in the 1967 Wilson X31 irons, according to Jim (our resident expert on all old shafts) were a .344 tip diameter, he thinks. Looks like the Augusta name is on several different products over the years. It appears some were sold in UK, but not for sure on that. Identified “Augusta” on some putters from the 1950’s in the Wilson History catalog, but see no irons with that name in the catalog between the years 1932 and 2000. That tells me they were store line.
Sorry, but that’s all we have at the moment. Jim’s researching to see if he kind find out anything else. If you could send a picture, that would help. You could also remove a shaft and measure the tip to be sure.