Congratulations! Even though it was years ago, I recall exactly how painful it was to get the plugs out of my 1200 tranny and diff ...

I couldn't help it, I had to look up what a "Metrinch spanner" is ... for us americans it translates to "modified combo wrench". Instead of hex or 12-point box-end, it has a odd 6-cam-shaped end, supposedly to grip on the flats of the bolt instead of the hex edges. I'm actually surprised it worked for this purpose ...