I saw someone on Coin Community recently say that an old Coin Monthly had something about the different rim width 1967 halfpennies being struck at different mints. Would anyone happen to remember that article?
And more broadly, are there any other articles that mentioned what was struck at the two mints and when? I've always taken the simplistic approach that all the predecimal stuff was probably struck at London, but what I saw now has me wondering if maybe the 1970 proof varieties are down to the two mints as well.