Alepax wrote:
I am now able to answer my own question. The Schmid Eb-alto triple that I attempted to put into "A" was one which I had on trial and was thinking of buying, secondhand, from a well-known UK horn retailer. I decided against buying the horn. I have since discovered that the Bb main tuning slide was missing an "H" section. It should have had two "H" sections but only had one. The retailer hadn't told me this (probably due to ignorance). I have now bought an identical (secondhand) Schmid privately. Not only is this complete, but in much better condition and a lot cheaper!!
That is a success story. Buying privately is the old fashioned way of doing things and has worked in your case.
It's a shame to think that there are any 'ignorant' horn retailers out there.