Hmmm... didn't spot the neck being that high. That photo might have been when I initially rested it all together for clamping/drilling before I realised that there were pre-drilled holes in the neck and I should check those first, after which I took the string off, screwed it together, and put the string back on.

Guess I'm doing it all again! Maybe I'll put the tuners on and use the actual strings. With the neck screwed in and the cotton thread on it didn't look like the neck was sitting high, but that photo sure looks like it, or at least much higher than on my p bass.