Just got a double horn (this one: https://www.amazon.co.uk/dp/B0012INK88/ref=cm_sw_r_cp_api_i_8R97DbHGJJGMR) and it came naturally as F (without thumb valve). Is there a way I can change it so I don't have to press thumb valve for B Flat side?

Any help would be appreciated,
Eddie

It appears that if you were to unscrew the mini-ball attachment on the change valve and screw it to the other side, you would having it standing in Bb rather than F. It is hard to see, so can't be sure. Most European horns have a similar arrangement because Americans tend to be taught to play in F and change to Bb while most, if not all of Europe is taught to play in Bb and change to F.