Maybe it has to do with the “powerful” acceleration of the Scott. If the chamber is mounted on the back the fuel may be stopped to enter the chamber during acceleration. If mounted in front of the carb the fuel will be forced to flow in the chamber.
The float chamber on my 3 speed flyer is on the LH it partially covers the LH oiling union position but the recess prevents is coming further forward it is a top entry chamber but is not exactly vertical i don’t think its union is at the right angle to the carb body and so it has a slight lean forwards. Has anyone a picture of what it should look like? (27 Flyer)
The 1927 Flyer should have a horizontal carburettor mounting for a clip-fitting carb, onto a cranked alloy stub, which mounts onto the usual three-stud flange on the engine. The carb on later Flyers, TT Reps, etc., fits at an angle of 38 degrees, and so the float chamber mounting ‘banjo’ has a twist of 38 degrees in it to make it level.