Flyback transformer with extra pads added to PCB?

[Faringdon]

Hi,
"How do you terminate flyback windings to the pins of the former without the former pin melting out of its plastic holding when you solder the winding to the pin?"

The attached is a 30W non-isolated flyback with Vin = 390Vdc.
It uses an ETD29 Former. Extra pads have been added outside the former so that its easier to wind and assemble to the PCB (ie just have to wind a layer across and no “end” to bring back across the bobbin)
Also, de-enamelising enamelled wire and then terminating it to a former pin often ends up with the former plastic round the pin melting so much that the pin just falls off.
Why is such practice not more common in prototyping?