Thanks to both Tim and Nou.

I may have failed to change to the correct build directory. I tried again and this time got build errors relating to various properties not being defined or declared. I have the whole output if anyone is interested.

Then looked inside the repository, found indi-asi folder and the inside it which gave instructions for building the driver by itself. Tried these, they gave the same / similar errors.

So now I will try the scripts to which Nou refers, however, I will not be doing this on a clean image, because I have a pile of other things installed including CdCiel/CCDCiel, ASTAP (thanks to HAN who has recompiled this to work with Raspberry64 - see his Sourceforge page) and so forth.

Will get back here when I have tried this.