Seems awfully shallow for a flugel... I play primarily on a 1-1/2A which looks (albeit looks aren't a good way to tell) practically as deep. I have a Denis Wick 2 for cornet which is substantially deeper than this. Cool mouthpiece though! The modification must have been expensive but I imagine it was worth it.
That is B.S. from Andy Taylor the UK uses both Imperial Units and Metric and he is old enough to be my Dad maybe my Grandfather he grew up with inches and such!!! LOL.....NATO nations are very good at converting since all of our Tank specications where in inches and such. I am guessing he did not get his GCSE and such if he can not do a simple conversion like that. Imagine what would happen if he and his clients had to convert from 32F degree's to Celsius! LOL