Of course Tamiya do not include all the parts you need on one sprue and you have to fork out another 40 Euros for Sprue "B",

To make matters worse Axels do not know when Sprue "B" will be in stock.

Looking closely at the Heng Long "Early" Cupola and the Tamiya "Late" Cupola the only obvious difference is the early has a hinge for the split hatch on each side whereas the late has one hinge for the one piece hatch,
The Hatch dimensions are the same in both the early and the late,

File the ridge off of the split hatch and smooth the area of the hatch that was hinged to the cupola,
Glue both parts of the split hatch together.
You now have a late model Panzer 4 Cupola and you have saved 80 Euros.
