Mine does not have the in-flight mixture control but otherwise it is the identical carb. I can't tell by the picture but it may be that that constant diameter brass section will slip off and then if you remove the lever arm assemble you can reinstall the needle and you will have a normal set-up.

I'm sure that there are other carbs that will fit i.e OS Super tigre Perry etc. You can also just lok the arm down.

Denis