To my knowledge, the Jane has a Spanish bottom bracket (consisting of two bearings that press directly into the bottom bracket shell, a spindle, and a spacer tube that the spindle runs through and keeps the bearings from being side-loaded), so there isn't anything preventing the spindle from coming out other than age/corrosion. I hesitate to recommend that you just "hit it harder," because that can damage the ends of the spindle where the crakarms and fixing bolt go, so give the penetrating oil some time to work. Re-apply often, and lay the bike on its side so that it flows between the spindle and the bearings. Flip the bike over and do the other side. When you do get the spindle to give, go ahead and replace the bearings; they'll likely be contaminated by the same corrosion that has frozen the spindle in place.
