If anyone is interested there is a free PDF download of a very good, but old late 19th C book on bronze weapons etc of the UK and Ireland ...fair number of illustrations. Go to link ...on left hand side theres a small 'box', locate PDF, right click.. 'save target as' ...download to 'My Docs'. Worth searching on this site for other interesting titles.
In this book are references to chisels, some are socketted, most look like the one's in the picture below....not one shown looks remotely like Fernando's 'first' example.(with sprue) Many of the designs and form for most implements were fairly common all over Europe. One reason being that trade for tin brought many continental traders to places like Cornwall where the exchanging of ideas etc were common. So it is unlikely that this design was unknown in Britain.