Thanks for the reply, leafo. Unfortunately the error for downloading the app persists even when I try different VPNs, or switch off the VPN completely. I think I might try downloading it on a different PC within the household and see if the error still happens.
Also, regarding the game I bought, I've managed to get the download going by enabling the alternate download mode, however the download always fails around 1.0/1.3GB, saying "Failed - Server Problem". I've tried 13 times, so it's definitely a consistent error lol.