Dutch from English + English from Dutch
Is it possible to do both language courses, or will my Dutch from English go away if I switch courses?
You can do it. I started off with the English for Dutch speakers to practise whilst I waited for Dutch for English speakers. My progress hasn't disappeared from either, but to access the trees again and your progress you just have to switch in settings. It's a bit tedious but it doesn't lose your progress.
Agreed. Plus you do more translating into Dutch (on Eng for Dutch) than you actually tend to on the "learning Dutch" course I've heard. I feel it helps me apply what I've learnt more especially as it's more immersion and I actually have to take more time to read what is there rather than be like "Oooh English everywhere" (with the UI being in Dutch etc).