Finally got the tumbler out. It has a separate locking tab. Use the same wire tool but I found two seperate wires worked better.
Took about 1/2 hour - for some reason it wouldn't release then suddenly it fell out into my hand. There is only one catch on the tumbler itself and it is on the side away from the column. Funnily enough I was fiddling with the other side when it fell out. So maybe I was pushing the tumbler over - taking up the slack? The locking tab is smaller than the pics I have seen and it is black plastic, half way along the tumbler. This may help anyone else having this problem.
But the saga continues...
I ordered the parts and then starting putting things back together. The little clips that hold the cover were kind of loose so I had removed then so as not to lose them. They have a little tiny spring that tips them out and locks the cover. Well small as it is, sprooong and away it flies!! You know that little gap between the centre console, the carpet and the main dash? Just has a couple of cables in it? Well it didn't even touch the sides! A couple of little tinkles and rattles tells me that I better go back and order up a new switch body. lol
Here is a pic of my tumbler with my pin in it. The black piece is the locking tab.
http://www.peachparts.com/shopforum/attachment.php?attachmentid=72682&stc=1&d=1253830602
If your pin is too thin try bending it a little and then rotate it to press the tab completely in.
A couple of other things...
DON'T remove the carpet - the '93 400E has an electic speedo.
DO remove the cluster and drop the steering wheel - gives you much better access and you can do most of this sitting in the driver's seat.
If you think you might have this problem and are ready to fix it, then every time you park your car extend the steering wheel fully and move the driver's seat back before turning off the ignition. And if you're in a garage, make sure your wheels are straight!
Seems like all these cars are a little different so if anyone needs more detail email more or reply to this post. Be glad to help if I can.