Should have taken 10 minutes, but took over an hour.

The soft-close seat was not closing softly after almost 6 years of use,
so I got a replacement. One of the nuts holding the old seat fixing
undid fairly easily with the supplied plastic socket. The other one did
not. Using a spanner just resulted in the 70mm-long threaded S/S rod
turning as well, but the top end of the rod was hidden under the round
metal seat fixing on the top of the pan, so I couldn't grip it. A squirt
of WD40 on the nut didn't help.

I decided to use a mole wrench to hold the lower end of the rod while
trying to turn the nut with the spanner. But I was aware that if I
crushed the thread I would not be able to get the nut off the end. But
whatever I used as a pad between the wrench teeth and the thread was not
strong enough to prevent the rod turning with the nut. In the end I
decided to use the wrench without padding, and if the thread was damaged
saw off the rod with a Dremel (there was no room to use a hacksaw). I
got the nut turning without the rod, but then noticed the rod was
slightly out of true. Carefully straightening it allow me to get the nut
off somewhat more easily; fortunately the thread hadn't been damaged by
the mole wrench.

Of course, all this was done in a most awkward position, and with the
knowledge that too much force in the wrong place could lead to an
expensive replacement for the pan!

--

Jeff