Smiths Heater internal baffle?

[Ed]

Guys,

While fixing my heater (smiths beehive) i noticed that not much air would be forced to turn into the ducts for the windscreen demisters.

I noticed around the fan motor 3 screw holes.  Is there some sort of plate or baffle which fits here to force the air into the ducts, rather than letting the air pass by?

In any case I made a quick and dirty "baffle" that now forces air into the tubes. 

I figure there must be one fitted normally???

any ideas?

Cheers

Ed