Wondering if anybody else is having problems with Netflix offline downloads while on a degrees connection?

I'm using an iPhone 6s on iOS 10.2.1, when I try to download any show using the Netflix app it thinks about it but then fails. Streaming works fine, just not downloading. If I turn off my wifi and try the same on Spark 4G cellular it downloads immediately.

Have tried rebooting phone and deleting / reinstalling the app with no luck.