Hi, Paul, Moira, and all.
Thanks for all your comments, the main reasons for not using the INOtherapy INOVent transport Head are the size, and weight, have you ever tried lifting one? I do two service exchanges every year, and I would not want to add that weight to the transport incubator!
Also the battery life is not really for mobile operation.
I have been told about Nox Box from Bedfont who do Smokalyser and exhaled Nitric monitoring amongst other things.
Regarding the lack of servo function, we have lived with that for years, the vent is a BabyPac from Pneupac, and Nitric and NO2 had to be monitored as Moira said, periodically.