We completely redesigned the breath pipe between the 2.2 which you played in Birmingham and the 2.3 Alpha, which is what we ship. This was to both remove noise (which everyone who played 2.2's complained about) and to improve the sensitivity. We also had complaints from people who, when playing a lot, kept dribbling down the front of their shirt. This wasn't an attractive feature.
Reactions from people who have played both have been very positive so far - the new design feels a lot more reactive, is quiet and spit now exits the instrument from the bottom straight on to the floor. The downside is that we lost the ability to adjust the breath bypass amount, so we had to choose a value for that. I picked on the amount needed for a Harmonica which is a low air volume instrument. There were three reasons for this. Firstly it's a lot easier for anyone who is not a trained wind player - I personally find the amount of air a Sax requires to be a real problem. Secondly, the physical constraints of the air path through the whole body of the Alpha or Tau make it very hard to accommodate large volumes of air flow without making the instrument a lot larger. Thirdly, the low air volume is enough for good articulation and expression, but still makes circular breathing a possibility for us mere mortals (my friend Ian Ritchie can do this on his Soprano Sax and it's always made me jealous). So there were a whole load of reasons for the redesign, and it seems to have worked out well. Dave, who is a Saxophonist has got used to it and likes it a lot. The fact that I'm a Harmonica player had nothing whatsoever to do with this design decision of course!
You should however experience a noticeable and distinct airflow through the pipe, and if this is missing then there may be a blockage. This will also make it hard to play the pipe well. We should certainly have a look at that as soon as possible, to make sure that you don't have a problem. If you can make it to London, Dave and Aaron could check this for you, or if you are confident that there is a problem we'll get the instrument collected and check it in Exeter. We will be doing another London event, but probably not before April (Musicmesse in Frankfurt looms at the end of March, so we'll be very busy running up to that) and you shouldn't struggle on if there's a fault, we should fix it for you.
John