Thanks so much Lee. Where else would you be offered such fantastic support on what appears to be such a small item. (not!).
I think I now understand why the pin just is not just drilled out . It appears to be of a harder material than the surrounding upright metal and if you should get on the edge of the pin the drill bit drifts off and you wind up with a hole partially in the pin and partially in the upright. Less than ideal and likely drilled not absolutely straight.
Just saying this because it once happened to a friend ......!