JTC,
Interesting point about the Lynx.
Confirm it has an anticlockwise when viewed from above rotor?
I'm just thinking out loud here, but there could be a couple of effects at play when you pitch forward -
Firstly, there should be a reduced inflow at the front of the disc and increased at the rear due to your pitching action which would tend to increase the angle of attack at the front and reduce it at the rear.
That should produce a rolling moment to the right, I think.
Secondly, if gyroscopic forces are significant, you would be providing a 'downward force on the front of the gyro' which should manifest itself as a roll to the left.
So I guess in balance, the aerodynamic force appears to be the winner (!)
Anyone else got ideas about it? There are probably a bunch of other things influencing the motion, even assuming that you kept all the controls relatively still once the pitching was initiated.