I design and build high precision photogrammetry equipment. It's nice reading this knowing I'm a part of this story, just half a millennium further down the road...
I started my engineering career as a land surveyor, not as a software developer. 2008 and the commercial property market crisis damaged the surveying business enough for me to make the switch to developing FT.
So, if I wanted to just get a practical feel for the basics of land surveying (this is the big distance sort of thing), is it enough to mock up our own horizontal sighting instrument, or is the vertical part of the theodolite vital as well?
It is vital. The first measurement you take on set up of the theodolite is the height of instrument (usually taken with a folding ruler or tape measure). You measure it from the base of the theodolite/total station to the top of the control point.
Are there any good "basics, probably with your kids, guides"?