store iPlayer downloads on SD

[MrMister]

I have a Moto E with v4.4.4 on, it's not rooted, just a standard SIM free phone.

I have official iPlayer app on but as Moto E has limited internal memory as soon as I try to do a iPlayer download for watching later it says "not enough space"

I can't see any option in the iPlayer app to store on SD are we stuck? Surely there must be a way, a lot of Android phones have limited internal memory. Haven't the developers thought of this? I understand about the DRM etc but it's very limiting.

Thanks