Wow, glad you got it sorted. Google "spark erosion" as a means of stud removal it's amazing.
Out of interest, all the emissions stuff is that the same on the UK supplied cars. I know on mine, by 1969 they had to fit all sorts of extra gumf to comply with US regs gradually sapping the power output from an original 265bhp down to 200 if you were lucky. It's the reason they switched to a 3.54 diff for the US market.By the early 70s the e type was 10 years old and a bit long in the tooth,the 240z being one of the bigger nails in its coffin!!
Anyway keep up the good work.