Thank you to everybody for the replies,
ahramin
We did contemplate cutting the engine with the Fuel Cut-Off like you discribed. The only reason we didn't do it is because the aircraft is fitted with a Telematics as well as an ADAS system and we thought it might trigger all sorts of bells and whistles at home base. Thought we better advise them before we attempt it, just in case.
V1... Ooops
When we pulled back the power lever during the test it took a long time for the propeller to start the feathering process, but once started it seemed normal. In other words the first condition you described.
Thanks again,
Prop Job