All golden advice, thanks fellows. And kudos on surviving being Stockhausen's student!

The boss likes the system, but we'll have to split it in two phased orders. In the long run this means more modules, as we can fill two LC6s.
Here's what I came up with
ModularGrid Rack

Some of the modules you suggested are tricky to source in the UK (largely thanks to Brexit...), and the budget needs to be spent quite soon. So I went with what's on offer currently. I like the Isolator, but I also read good words on the Befaco output. Unfortunately no Maths or Beads until the autumn, so I added a few bits for s+h.

And yes, you convinced me on portability.
Am I right to thing that the Doepfer P6 is somewhat bad value, considering the LC6 and a made-to-fit flightcase would be cheaper?

Thanks again to both for the advice, incredibly helpful!