Typical that the front elements are a spaced doublet. And typical that the outermost part of the lens barrel is hold the front element in place, not the whole lens block. Some TLRs have what I consider the main body come off, the only thing I can get a grip on, leaving a minuscule stub of a rear barrel and the rear element.
Using a spanner wrench, best to lock the spacing. Cover glass with a microfiber clothe. Sometimes, depending on the width needed, using a air of pliers to grab the wrnech from the side, getting both legs in the jaws, while using the other hand to keep the spanner in place from above, can be good. And once the spanner loosens it, a fingernail or small flat balde screwdriver can be used rather than keeping that big floppy chunk of metal by the glass.