I had my first experience of using a seat with a sunken base, noticing the metal bar a couple of weeks ago - it was fairly uncomfortable but I’ve always found the seats fairly uncomfortable on the IETs as if I’m sitting up straight, the top of my shoulders rest where the head rest is which pushes them forward and gives bad posture. Better if I slouch a bit but not great for your lower back.
Toilets being out of service seem to be more frequent too. I was on a 5 car IET with the coach A toilet out of use, and twin cubicles opposite each other also taped out of use further down in another carriage. Issues with toilets don’t seem to be a new thing though, when I regularly commuted by train a few years ago, it was common to have 1 or 2 toilets locked out of use on the 158s. Some of the smaller toilets on the three-car 16x have also been out of use for years, though it does look like they’ve started replacing the toilets now.