Here's a sneaky trick that might save you a bit of effort and frustration- - - - - -grind the back of a fine-toothed hacksaw blade down until it's narrow enough to fit into the guide you've drilled out, and carefully cut a slot or two almost all the way to the edge of the guide. Then make a piloted driver and give it a good whack with that BFH. Chances are that by weakening the shell of the guide by slotting it you'll be able to make it move without going to extremes making more tooling. Just be careful not to cut into the head casting while you're slotting the guide.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!