Playtime has the same diesel tank and freshwater tanks but there is a space, about 25cm wide, between the tanks down the centre of the bunk – this is where the units are normally fitted and it is easy to route the ducts from there (and the control unit by the bed!).
If you use the ER, I’m not sure how you get the duct to the forward cabin (maybe you don’t?). You may also have to route a ‘clean air’ inlet for the unit if you don’t want ER smells distributed around the boat!
Sorry to hear you’re having bad weather down there. We had the hottest summer on record this year (global warming?). However, it’s getting towards winter now – only 18C today!