Time Trial / Time Trialling / TT

The point you keep missing is everything prior to a tunnel or velodrome test. You or I thinking up a set of tests to do in a tunnel is an incredibly expensive way to piss money down the drain, you'd get through that £10k pretty quickly.

Maybe helmets is the only thing you want to test then fine, but spending time and money on someone who, based on your specific aims, budget, current equipment setup, performance data etc etc etc will work through whether testing helmets is even worth doing let alone a starting point.

Consultancy doesn't tell you that x is definitely faster than y for
most things on you or your bike - there's too many interactions and
where there's not, most people already know the answers.

Of course it can't, that would be ridiculous. Unless you find someone who can 'see' aero...