I'm just finishing the first season with a bunch of Abelo boxes which are my only all poly boxes. I have other mixed Sweinty + wood combinations. I get much more condensation in the Abelo boxes. I'm not aware of it in Sweinty+perspex crownboard+insulation. In the Abelo boxes there are often little puddles underneath the frame lugs.

I've had to get a second shed to keep all the little plug in ventilation blocks Perhaps I should use them instead?