Tuc, I'm not familiar at all with any extant ANR systems (apart from the Harrier one) but the specialist may have been. His main MOD poc was the IAM (or RAF CAM or SAM or whatever they were then) as it was seen as an aeromedical matter. I may be wrong but they should know about such things. The challenge with the F35B was the sheer intensity of the noise, far above normal military cockpit or cabin levels. In-ear devices had difficulties with the energy levels even with a well designed helmet and as stated before, the failure behavior was a problem. I confess it wasn't a long conversation but at one point we mused on the possibility of using cockpit side skins as a source of countering noise. Maybe not a serious possible solution but perhaps the panel size does indicate the difficulty the noise intensity levels created.
EAP