But are those demos being re-calc'd in real time?

With offline processing writing to a (big) file any modern system would be powerful enough. If you want to make 1 change a day and leave it to re-calc over night.

But for twiddling (even controlled parameter twiddling with a method-of-experiments plan) something a lot faster is needed.

So where those demo's being done on the fly?

Otherwise just what the Interception Modernisation Programme needs. Now all they need is some of that magic find-all-suspects-with-a-matching-comms-pattern software GCHQ seem so keen on.

How hard could that be?