Geriaviator
Yes, the Blenheims were dual-controlled. We had Mark I's and IV's, short nosed and long nosed. Cockpits were most uncomfortable, broken ends and sharp bits of metal seemed to be sticking out everywhere. We didn't use goggles for night training. Magisters under the hood for instrument training - yes that was routine.
One interesting item I don't think I've mentioned elsewhere; most veterans will know about the carrots and good eyesight furphy that was made public was that ``Wg Cdr John Cunningham ("Cats-eyes") owed his success to carrots. The story was put out to keep radar secret, and we did get more than we wanted in our meals. In fact carrots contained a soporific discovered long after a number of young pilots lost their lives by falling asleep at the controls. I think 5 died on our course; one was another mate, Harry Beck who went out on a solo night flight and came back in a bag.