Mine were B*****S. Ended up drilling them out very carefully. managed to salvage most of the threaded insert. Replaced all fixings with Stainless and lots of antiseize. Even managed to get nylock nuts on the inside of the wing.
It was only then that I dropped my spanner and it dissapeared from sight.
TIP: When using a spanner in a confined space where it could drop out of sight, or worse, reach, tie a bit of light cord to the spanner and somewhere out in the open at the other end.
You can now play that excellent trick, spoon, jar, jar, spoon. (appologies to Tommy Cooper)