Even though I never tried , and never hope to try, apparently the 145 can be flow without hydraulics in the event of a dual failure, the 135 however is a no go.
With a rigid main rotor head, exactly the same as a Bo105 and BK117C1, and flexiball controls, I doubt it very much!!
As Spinwing says, both hyd systems are active (pumps running) but #2 is in bypass (no pressure) until #1 fails.
A Bo105 in the UK did have a temporary (long enough to scare the sh*t out of the pilot) dual hyd system failure, in flight, about 4 - 5 years ago.