I haven't seen my little guy since I was 18 weeks as well. But my midwife checks to see if he's head down which he is

Is that a midwife thing??

It was the same for me with my last pregnancy. With my first they were worried about low amniotic fluid which it turned out to be the case and with my second they were worried about fluid in his kidneys(which went away) so I got another ultrasound at around 38 weeks for both of them. With my third the worry wasn't there so I didn't need an ultrasound after the anatomy scan.

That's how it was for me. But don't worry they can feel from the outside of your belly if baby is head down (creepy ino lol)

That was mine too, but I paid for another at an outside clinic at 27 weeks