Our company has just trialled three ANR headsets, the Bose X and the Sennheiser HMEC 25 and 46. I think the preference overall was for the Bose, however of the Sennheiser models the older HMEC 25 came out on top. We operate 733s and had to have the units with the battery pack in them. This may also be the case with your NGs, but it should be very easy for you to find out next time you fly.
P.s. I reckon the airline should be paying for those sorts of things, health and safety reasons etc.